Released: Cumulative Update 6 for Exchange Server 2013

Note: We have learned that customers using Exchange Server 2013 and Exchange Server 2007 co-existence can experience an issue causing Exchange Server 2013 CU6 databases to failover. Please refer to KB2997209 for the specific scenario impacted.

The Exchange team is announcing today the availability of our most recent quarterly servicing update to Exchange Server 2013. Exchange Server 2013 Cumulative Update 6 and updated UM Language Packs are now available on the Microsoft Download Center. CU6 represents the continuation of our Exchange 2013 servicing and builds upon Exchange 2013 CU5. The release includes fixes for customer reported issues, minor product enhancements and previously released security bulletins. A complete list of customer reported issues resolved in Exchange 2013 CU6 can be found in KB 2961810. Customers running any previous release of Exchange 2013 can move directly to CU6 today. Customers deploying Exchange 2013 for the first time may skip previous releases and start their deployment with CU6 as well.

We would like to call your attention to a couple of items in particular about the CU6 release:

  • As discussed at MEC 2014 and other forums, CU6 includes significant improvements in Public Folder scalability. More details about this in Public Folder Updates in Exchange 2013 CU6: Improving Scale and More.
  • CU6 includes a fix for the HCW issue discussed in KB 2988229. A reminder for those customers who installed the Interim Update which resolved this issue: it's NOT necessary to uninstall the Interim Update prior to installing CU6.

For the latest information and product announcements about Exchange 2013, please read What's New in Exchange 2013, Release Notes and Exchange 2013 documentation on TechNet.

CU6 includes Exchange-related updates to Active Directory schema and configuration. For information on extending schema and configuring Active Directory, please review Prepare Active Directory and domains in Exchange 2013 documentation.

Reminder: Customers in hybrid deployments where Exchange is deployed on-premises and in the cloud, or who are using Exchange Online Archiving (EOA) with their on-premises Exchange deployment are required to deploy the most current (e.g., CU6) or the prior (e.g., CU5) Cumulative Update release.

Note: Documentation may not be fully available at the time this post was published.

The Exchange Team

Comments (126)
  1. Anonymous says:

    @Peter4534532, @Ackmania, @Peter, @OceanOB: We updated to CU6, crashes still occur, but far less frequently. It’s gone from several index crashes a day, to once every couple of days. Everything looks smooth. (So far)

  2. Anonymous says:

    We’re hoping the random mailbox/index crashing has been resolved in this one. Random daily database failovers are getting pretty boring.

  3. Aaron Marks says:

    @Brent Alinger, I contacted PSS multiple times and neither Tier 1 or 2 support were able to assist. They informed that I need to wait for Tier 3 to come into the office on Monday (India time, our Sunday in the US). I have called in today (Sunday) as well
    and have yet to hear from Tier 3 with a download to the hotfix that I’m requesting by name. This probably worth looking into because I’m sure others like me that need this fix are struggling to get it.

  4. @Brent and Other MS PG Group.
    Brent seems busy so please respond we are getting many issues logged on our blog.
    Below the latest issue reported by Muhammad here –

    After installing CU6, users started experiencing problems with Inbox Rules.
    Rules don’t work at times, also outlook crashes when you open rules and alerts or rename a rule.
    our Exchange 2010 users are perfectly fine, exchange 2013 users all have this issue.

  5. Anonymous says:

    @OceanOB we had similar issues with communications from them. MS support thought we were fighting two different issues. In fact we were fighting the same issue. The issue was that exchange 2013 CU5 tries to talk to all global catalogs. We have our network
    segmented and our systems can’t talk to all domain controllers…… This was causing a lot of our issues. Now with CU6 it is way better. I would go as far to say CU6 is the most stable release to date.

  6. @PrabhatNigam,
    Good, but why on the first server Ece (updated) service is started and running?

  7. "Reminder: Customers in hybrid deployments where Exchange is deployed on-premises and in the cloud, or who are using Exchange Online Archiving (EOA) with their on-premises Exchange deployment are required to maintain currency on Cumulative Update releases."

    What do you mean by this? How many CUs is a customer allowed to fall behind?


  8. Ed (DareDevil57) says:


  9. Aleksey Medvedovskiy
    If Test-servicehealth shows any service is not running then you need to worry else you are good.

  10. Please add Set-MailboxSentItemsConfiguration cmdlet back!

  11. Huh, I think that my random switchovers in CU5 was because of lags on ESX virtuals… interesting.

  12. OceanOB says:

    @NahanHD, @Ackmania, @Peter: we also have nearly daily DB failovers in CU5 servers. Actually, we kept most servers in a previous CU because of that.
    We have a call opened at MS, but didn’t get information whether CU6 is solving it.
    We are planning the test of CU6, but if one of you test it faster, please say it.

  13. OceanOB says:

    #JohnBair: What ECP, Address Book and PowerShell issues were you having in CU5 that have been solved in CU6?
    We currently have poor ECP performance, many times disconnecting, performance problems when accessing Global Address Lists (for example from classic mode Outlook clients), and also frequent Powershell session disconnections.
    If you had similar problems and they have been solved in CU6, that would be great.

  14. OceanOB says:

    @Renat: We are also having issues with resource mailboxes since CU5: meeting requests are not forwarded to the delegate when we have a group defined (they are when the delegate is a mailbox).
    We actually opened a call at Microsoft, and have been told that it is solved in CU6. We have not tested it yet, though.

  15. Why was sound notification in OWA removed?

  16. @Brent,
    It seems we are getting more issues with CU6. Do you confirm all issues has been taken care?
    Is there any plan to update this blog or any link with all the issues and fixes? Recently reported issues are IMAP and Thunderbird “Command error. 12″ then OWA web ready issue and extra line breaks in message body were being removed in Outlook online when drag
    and drop to pst or to another mailbox or to desktop.

  17. Does anybody know, that’s happen with "" file in CU6?
    How about automated install in big environments?

  18. Anonymous says:

    @NahanHD, @Ackmania, @Peter, @OceanOB: We have installed this into production and we have not seen another database fail-over since, it’s been in about 12 hours, we would have typically seen at least 4 fail-overs in this time frame before, so if it isn’t
    completely resolved it is at the very least better. There is a bit less event log spam as well (MSExchange ADAccess/3010, MSExchangeApplicationLogic, 3071/3073 have all stopped in addition to MSExchangeIS/1013). The update does break older management tools
    installs, so if you have service desk tools running on top of the management shell, you will need to update them quickly. All other aspects of service health look ok.

  19. Thank you Brent for the update.

  20. Could we also get KB2997209 published online somewhere? I would rather not go through the abomination that is Microsoft support just to get a hotfix.

  21. Anon-1 says:

    What a mess here…..Microsoft need to focus on testing & testing On-Premises CUs for the On-Premises customers before they get it……instead of Billion $$ Public Cloud Marketing we hear everyday………it shows Microsoft has dropped the ball here……Now
    we need Exchange Server 2013 CU6V2……

  22. And another one
    After installing CU6 servers are randomly rebooting from Bugchecks 0x0ef. Related to:
    ROCESS_OBJECT: ffffe0007194a080

    IMAGE_NAME: wininit.exe


    MODULE_NAME: wininit

    FAULTING_MODULE: 0000000000000000




  23. Good looking out @PrabhatNigam. We were going to install this next week, but I think we’ll hold off now.

  24. OWA sound notifications are NOT fixed. Are Exchange developers and QA are all deaf?

  25. @Martijn Westera/@Anon-1 – We have no plans to release a CU6-V2. We are able to address the issue affecting hybrid customers and 2007 co-existence without releasing a new version. We also do not want to disrupt the plans of customers and those who have
    already successfully deployed CU6 who do not need either of these capabilities.It’s

  26. @Aaron Marks – The KB2997209 update has definitely NOT been pulled and we have customer confirmation it resolves the issue. I have confirmed that all the appropriate support individuals should have access. If you are finding that a support individual cannot
    assist you, request that your inquiry be escalated.

  27. @Aleksey Medvedovskiy
    You don’t need "Health Manager Microsoft Exchange" on Edge and ADtopology is not there because it is not part of domain. I have answered the same question in my blog here. –

    Run this below command on your edge server to get the required services status

  28. Anonymous says:

    Ok MS tech just got me the hotfix, installed and testing server now.

  29. Looks like in CU6 still presents string error in mail-enabled Public Folders, tab "mail-flow settings" (Mail-Enabled Public Folder -> Edit -> mail flow settings ).
    Default choosen settings is:
    Reject messages from: All senders
    But it isn’t true meaning of string. If we look at Exchange 2007 documentation ( ), we will see, that correct string is
    Reject messages from: No senders

    And this is the correct string. It is very confusing, when you see that all Public Folders have enabled option "Refuse all messages from all".

  30. Issue Reported: Ryan reported on my blog that they are facing an issue with CU6 in exchange 2007 mix mode here. Any confirmation will be appreciated.

    Following issue reported.
    Do not install this CU6 if you have a 2007COEX with EX13. Were having major issues with databases flapping. This is due to EX07 mailboxes talking to EX13 mailboxes. MS are aware of this and working on a fix now.

  31. Anonymous says:

    You guys really underestimate this for use very BIG disadvantage: "Larger update packages". We have 20 on premises Exchange 2013 servers, about 12 of them are connected via vSAT (very slow link). Getting the CU’s to those location now have become an almost
    impossible process!
    – Downloading the large package via vSAT saturates the link to much, so our users will complain a lot.
    – Sending it via USB is an option but not always that easy (because some of the locations are Vessels). When the USB arrives with CU6, CU7 or even CU8 is allready available.
    – Copying via the network, will also saturate the vSAT too much.

    If the updates were small, instead of the complete binaries, just like with Exchange 2010, our update cycle would be way more doable and efficient. Thank you very much for making "servicing Exchange 2013" a very daunting and a nearly impossible task!

  32. Anonymous says:

    … and another BUG in CU6:
    WebReady Document Preview stopped working in OWA after Exchange server has been upgraded from CU5 to CU6 using Basic or Windows Integrated Authentication method for owa and ecp v-dirs which is a recommendation for eg. UAG or TMG based publishing.

  33. Will MS release CU6v2?

  34. Aaron Marks says:

    I contacted PSS and they were not able to supply KB2997209 hotfix. They informed me that the hotfix has been pulled or that the weekend support staff was accidentally not allowed to access it due to a permission issue. If someone from MS is looking at
    this, I have an open case (114082811752158) and please reach out to me if you can supply the hotfix.

  35. @BrianK2, @PrabhatNigam – We will be publishing KB2997847 later today for the 2007/2013 EAS proxy issue. All customers can now request a combined fix for both 2007/2013 co-existence issues. Both of these fixes will be available in our next cumulative update.

    @Renat Matveev – The OWA new mail sound notification is confirmed and will be addressed in a future cumulative update. KB2993499 (not yet published) is tracking this issue.

  36. Anon-1 says:

    Safe to say Exchange Server 2013 CU6, is THE WORST CU released for Exchange Server 2013………TOTAL DISASTER….need to get CU7 out ASAP……..please take care of your On-Premises customers…….

  37. @Brent
    Marcus reported a new issue at my blog –
    Exchange 2013 proxy for activesync WILL BREAK for legacy 2007 mailboxes – I am currently working with MS to resolve but so far there is no fix. They have multiple other customers with the same issue.
    Please share if you have any update on it

  38. Hello guys,

    I had a problem here in my environment with the installation of CU6 in Exchange Server 2013.

    Of the 10 servers that I tried to install 7 servers had the same problem, the qua displays the message "fms is not starting in Exchange Server 2013 SP1".

    Anyone here experienced this problem or could tell me how to solve this problem?

    Help Please!

  39. What a ridiculous excuse for a proper release. Or a standard release for Exchange 2013. Does MS realize that these installs aren’t destined for a lab? Some of us actually use 2013 in production?

    Upgrading 2007 as a "fix" for a 2013 bug is absurd. For one, it’s a lot more difficult to update 2007. For two, how about releasing proper code to begin with?

  40. Anonymous says:

    Deployed CU6 to a small production environment (2 Server DAG with 200 Users).
    Went mostly smooth, the only thing I noticed is that a complete index re-crawl happened. (after upgrading node 1)
    Took almost half a day for 150GB in 3 DBs. Server has 4 cores and 16gb, storage is iscsi raid10.
    Quite long for that tiny DB, next week I will update a larger environment with 2TB Data. I hope it doesnt have to re-crawl.
    After upgrading node 2 its content index state was stuck on unknown (events 1009 and 1010 were logged), I created the group "content submitters" and finally updated the catalog from node 1.
    all good since then.
    Before upgrading a node I put it in maintenance using $exscriptsstartdagservermaintenance.ps1.

  41. @Peter4534532 – We were not aware there is an issue downloading UM Language Packs. We will investigate and correct as necessary. Thank you for reporting this.

    @Martijn Westera – We do not expect Hybrid customers to fall behind. They need to ensure that they are remaining currency. Hybrid customers should be using CU5 or CU6 at this point.

  42. Anonymous says:

    Whats going on with the language packs, the link is broken. Have they been published yet? Can anyone else download them?

  43. @PrabhatNigam,
    Good, but why on the first server edge (updated) service is started and running?

  44. After the installation new Exchange Edge 2013 CU6 does not start service MSExchangeHMHost. error 7003 – Service "Health Manager Microsoft Exchange" is dependent on the following services: "MSExchangeADTopology". Perhaps, this service is not installed.

    Updated Exchange edge 2013 cu5 to cu6 – problems are not observed.

  45. @Bendoubitibly – Exchange 2007 update has released and tested. It is solving the issue. So make the use of it.

  46. Just finished 2 servers installation in lab, S1 installed perfect but on S2 some services were not started automatically so I started manully. I think it is because of my lab.
    Then created IP Less DAG and 2nd copy of the DB.
    Tested move DB to S2 then mailflow then move the cluster group to S2. All worked great.

    Earlier even in IP Less DAG, we were able to access the cluster from failover cluster manager by using dot but it seems this feature has changed in CU6. Can anyone confirm?

  47. Anonymous says:

    FYI – I received a combined hotfix for the Exchange 2013 CU6 issues (Exchange 2007/2013 DB failover/ActiveSync problem) yesterday. You’ll need to work with Microsoft Support to receive fix.

  48. regarding 2991934 ( ) Duplicate mailbox folders after migration to Exchange Server 2013 – we have CU4/SP1 in place and migrating mailboxes from E2007 – under
    what cicumstances this issue will appear? We indentified until now two affected users (more than 1000 migrated)

  49. So I wasn’t the only one with random daily database switch-overs! I have not really looked into it much as the process is seamless, however, backups are not too happy with this. If this doesn’t help that, time to open a call.

  50. @Jeff Guillet – You are correct, a solution is in the works for this (even over a holiday weekend).

  51. Thanks, Brent, I have confirmed that the script does fix the EAC issue. I have updated my blog article with installation notes here:

  52. Anonymous says:

    Ackmania: we are installing in a few days.

  53. OceanOB says:

    Thank you @JohnBair and @Peter4534532 for the information. This looks great for our installation. I only wonder why the MS guy taking care of our call didn’t tell us that the cause of the frequent failovers was already known and that it would be solved
    in CU6.

  54. Anonymous says:

    @NahanHD, @Ackmania, @Peter, @OceanOB: We raised a case with MS on this as soon as we installed CU5, they have now confirmed the bug is fixed in CU6 – we have yet to install it, but will be doing so early next week. We are seeing failovers occur very frequently,
    so will be able to confirm quickly.

  55. @Dmitriy – Command Line and unattended setup are still present in Cumulative Update 6. We no longer rely upon in Exchange Server 2013. Installation functionality is contained in SETUP.exe.

  56. Anonymous says:

    Sorry to be clear the issues we had were under CU5. They are all resolved with CU6. :)

  57. Anonymous says:

    @OceanOB – That is exactly the issue we were having. All web services were slow and random disconnects. Outlook clients would not be able to connect to Address book or room finder.

  58. Anonymous says:

    And now I feel torn…
    I’m just about to go live on a CU5 migration from 2007 in the next week or so, should I upgrade to CU6 and retest now or stick with CU5 and know what problems there are

    My heart says CU6 but my head is saying CU5

    And do the Dev team know if the UM language packs are going to get more transcription in the future?
    I was gutted that US, CA and a number of other languages have this included but nothing for the UK.

  59. @Brent
    We got another hit for OWA issue in coexistence with 2007 post patching KB2997209. This issue is reported by Vince and Brett. We are tracking the issue here –

    The latest resolution applied and posted by Vince is below:
    That’s it, the only difference is that we have 15.0.995.30 and not the 15.0.995.31. What we tried was to stop World Wide Web Service then rename the 15.0.995.30 version to 15.0.995.30_Original. Copied the 15.0.995.29 into a new folder and renamed it as 15.0.995.30.
    This way the 15.0.995.30 contained the files from the 15.0.995.29 version. Started the WWW Service and OWA seemed to work OK. This process was as per request from a Microsoft specialist who we still have an open phone call.

    It will be great if you can give me some updates.

  60. @PrabhatNigam – Yes, we became aware of this issue earlier today. This happens when a 2007 user attempts to access a delegated mailbox that is on a 2013 server. This issue is being tracked by KB2997209, that is still being published.

  61. Ackmania says:

    Yea, I’m having the same problem NathanHD. When are you guys gonna install CU6?

  62. Anonymous says:

    Do you have a list of feature changes in CU6 somewhere? Such as when you create a new shared mailbox, you can no longer designate a Send As permission during the creation. Actually, the creation was already cribbled in an earlier CU, when Full Access designation
    was removed (maybe in CU4 or CU5).

  63. Anonymous says:

    We loaded CU6 in our production environment last night. We had several issues with ECP, Address Book and PowerShell that were keeping the system from running smoothly. I would recommend running the CU6 before any cutover. It has turned our very smooth
    for us. -John

  64. Xypriz says:

    When can we expect to have the Set-MailboxSentItemsConfiguration cmdlet back? It is gone since the release of 2013 RTM and it’s really annoying to be forced to use those legacy work-arounds which are time consuming and don’t work half of the time!

  65. We have just released KB2997355 to the Download Center. This package provides a PowerShell script which can be used to restore normal Exchange Administration Center functionality after an Exchange Server is upgraded to Cumulative Update 6.

  66. Anon-1 says:

    Please TEST it in the lab 1st, and tell us here if All is well?
    Heading to the lab myself :-)

  67. @PrabhatNigam – Please have your customers who are experiencing these issues reach out to support services for assistance. This will ensure that the issue is fully understood and a product response, if necessary, can be provided.

  68. Anybody installed it?
    Questions for developement team:
    Was in CU6 fixed non-working sound notifications in OWA, broken since SP1?
    Any imrovements with Rooms reservations? Now have a lot of issues with them…

  69. Anonymous says:

    @NahanHD, @Ackmania, @Peter, @OceanOB: We are still experiencing store crashes resulting in database fail over with the same signature, they are far less frequent. If you are on CU5 it is still worth updating, if you are pre-CU5 then I still wouldn’t update.

  70. Anonymous says:

    I’ve had a similar experience to Aaron Marks, regarding obtaining the hotfix. Gone through multiple levels of MS support all telling me that the hotfix has been pulled. Even have a tech on the server right now, but doesn’t seem to be getting too far (he
    also is unable to obtain this illusive hotfix).

    Don’t see where i can escalate from here, if anyone can help me get my hands on the hotfix i would forever grateful. Case # 114090111757649

  71. Ackmania says:

    We’re planning to update in a couple of days (!)

  72. "Reminder: Customers in hybrid deployments where Exchange is deployed on-premises and in the cloud, or who are using Exchange Online Archiving (EOA) with their on-premises Exchange deployment are required to maintain currency on Cumulative Update releases."

    What do you mean exactly with this? How many CUs is a customer allowed to fall behind?


  73. adam says:

    Now I’m torn…
    Do I upgrade our new Exchange 2013 CU5 environment up to CU6 before it goes into full production in the coming weeks and potentially introduce new unknown issues or leave it on CU5 with known issues that are documented. My heart says CU6

  74. Dan Lee says:

    While you should typically proceed with caution when dealing with updates, I’d like to remind everyone that this is a new era for Exchange and their updates. These changes that we are getting for our on-prem environments have been in production for the
    Office365 hosted environment for some time now. We don’t get the release until they have been scrutinized in a production environment.

  75. mwk says:

    Have upgraded to cu6, addresses several issues that I had in cu5. Runs very well.

    I have noticed a new folder located at:

    C:Program FilesMicrosoftExchange ServerV15BinSearchCeresDiagnosticsETLTraces

    that is consuming a tremendous amount of disk. 1.4GB in less than 24 hours. Files names are

    DocumentProcessingTrace_1.etl, DocumentProcessingTrace_2.etl and so on.

    Currently have 29 of them in less than 24 hours, each file is 50MB. Did not have this in cu5 at all (or perhaps I turned it off accidently?

    What is this and can it be limited? Small exchange network with five users.

    Thks for the fine work.

  76. Daniel says:

    Have the change the logging level yet, or do I still need 100gb free disk space on C: ?

  77. Maurice says:

    Implemented CU6 last night on CAS and MBX servers without any issues so far.

  78. Pavel says:

    in CU6, database provisioning is broken. In CU5, when moving mailbox from 2007 to 2013 I was able to use parameter -TargetDatabase (in New-MoveRequest) for DB that is excluded from provisioning and now in CU6 this DB can’t be used as target DB :-(

  79. Leon says:

    @renat mateev, wow i thought we were the only one on a customer site. random switches of the DAG. we thought iscsi issues on switch, looks like it was an exchange problem.

    @microsoft, is this solved in CU6? could not find anything mentioned in the release notes.

  80. Mike Virgilio says:

    I installed CU6 to 3 exchange 2013 Standard servers yesterday. The install went fine, and all systems appeared to be up. I woke up this morning to 7000 alerts (I have all error/warning event logs emailed from exchange servers to a distro group) that a
    service was repeatidly crashing over and over. On two of the servers, the service called "MSExchangeMigrationWorkflow" starts, crashes and then repeats (the recovery actions are set to restart the service). On one of the systems, it’s running without problems.
    I have tried a second reboot on the two which are crashing (the servers were reboot after the CU6 update was installed), but that didn’t help. I have configured the recovery options on those failing servers to "take no action" and have been searching internet
    on potential fixes. I figured I’d post here since it’s so new and this should get to the developers.

  81. Mike Virgilio says:

    Beyond the event logs recording the service starting and stopping, I am also getting this alert "Watson report about to be sent for process id: 10088, with parameters: E12IIS, c-RTL-AMD64, 15.00.0995.029, MSExchangeMigrationWorkflow, unknown, M.E.M.L.L.<>c__DisplayClass11.b__10,
    System.NullReferenceException, 49af, unknown.
    ErrorReportingEnabled: True

  82. Ariedebeuker says:

    In post in social technet forum it is said If you have Exchange 2013 CU5 & Exchange 2007 SP3 RU11 in a coexistence setup then OWA proxy is broken/not wokring.
    Does this also apply for Exchange 2013 CU6 with Exchange 2007 SP3 Rollup 12 ?

  83. Mike Virgilio says:

    I installed CU6 to 3 exchange 2013 Standard servers yesterday. The install went fine, and all systems appeared to be up. I woke up this morning to 7000 alerts (I have all error/warning event logs emailed from exchange servers to a distro group) that a
    service was repeatidly crashing over and over. On two of the servers, the service called "MSExchangeMigrationWorkflow" starts, crashes and then repeats (the recovery actions are set to restart the service). On one of the systems, it’s running without problems.
    I have tried a second reboot on the two which are crashing (the servers were reboot after the CU6 update was installed), but that didn’t help. I have configured the recovery options on those failing servers to "take no action" and have been searching internet
    on potential fixes. I figured I’d post here since it’s so new and this should get to the developers.

  84. Tim Maung says:

    CU6 UM language download link is missing. How can I get it?


  85. sam says:

    UM Language Packs Link is broken.

  86. Ilja says:

    Why the sudden change of colors in OWA? Blue/black theme in OWA is suddenly light blue with green highlight on messages/folders. Several other themes are also affected.

  87. Tharaka says:


    After updating to CU6 I get MSExchange RBAC 74 errors. I’ve no idea how to rectify this. Any ideas..

  88. M Kelfer says:

    CU6 has introduced a series of files located at

    C:Program FilesMicrosoftExchange ServerV15BinSearchCeresDiagnosticsETLTraces

    The files are numbered sequentially and named:


    and are 50MG each. I currently have 55 of them utilizing 2.5GB of disk. What are these files and can they be somehow controlled so as to not take up as much disk? This was either disabled in CU5 or (accidently) turned off.


  89. Adi says:

    any updates on the missing "Move to exchange online" menu ? ref:

    I also have an issue with centralized mail deliver in a hybrid environment where exchange online users gets relay access denied when sending to external users

  90. Luke Swinkels says:

    Just had the same experience with MS support. Told me the hotfix was pulled and that they could not supply it.

  91. Himzo Mihaljevic says:

    Hi, There might be an problem with proxy EAS to 2007 with CU6, we are currently working on a case with this symptom.

  92. Adi says:

    anyone else having trouble in a hybrid configuration with Centralized Mail Flow enabled ? my exchange online user is unable to send email to external users with the NDR returned with relay access denied originating from the hybrid server

  93. Nick Lowe says:

    Please can you release this hotfix publicly ASAP even if it’s with warnings that it is preliminary and subject to further testing. Thanks!

  94. anon-99 says:

    I installed CU6 to 3 exchange 2013 Standard servers yesterday. The install went fine, and all systems appeared to be up. I woke up this morning to 7000 alerts (I have all error/warning event logs emailed from exchange servers to a distro group) that a
    service was repeatidly crashing over and over. On two of the servers, the service called "MSExchangeMigrationWorkflow" starts, crashes and then repeats (the recovery actions are set to restart the service). On one of the systems, it’s running without problems.
    I have tried a second reboot on the two which are crashing (the servers were reboot after the CU6 update was installed), but that didn’t help. I have configured the recovery options on those failing servers to "take no action" and have been searching internet
    on potential fixes. I figured I’d post here since it’s so new and this should get to the developers.

  95. Brook says:

    The lack of CU testing and validation reaches a new dimension…any news regarding hybrid setups and holding off on installing CU6, as Jeff Gulliet posted ?

    Urging hybrid customers to keep up with the CU releases is surreal =

  96. Dae says:

    I’ve had the following problem on a number of fresh build 2012R2 servers with greenfield installs of 2013 CU6 in freshly built domains with 2012R2 DCs:

    After install you get the event 1310 from source " 4.0.30319.0" logged many times, each complaining that DLLs could not be loaded for each of the virtual directories as "the file specified could not be found". OWA and ECP wouldn’t load and just returned
    the "something went wrong :-(" page.

    After a couple of days of investigation it seems that the sharedwebconfig.config file hadn’t been created. All the web.config files in each of the virtual directories were trying to load modules, like antixss, but the server didn’t know where to find them as
    the paths to these files are now stored in the sharedwebconfig.config file, which for some reasons wasn’t created on each of my servers experiencing the problem.

    Looking at CU5 an earlier servers, each of the web.config files have full paths to the DLLs. It therefore seems that CU6 has transitioned to a "shared config" approach rather than repeating all the paths in every web.config. Once I found a working CU6 server
    I just copied the sharedwebconfig.config file from c:program filesMicrosoftexchange serverv15clientaccess, did an IISRESET and everything started working.

  97. BrianK says:

    I have CU6 Hotfix for Exchange 2013 database failover issue when in mixed mode with Exchange 2007/2013, but is there ActiveSync issue for Exchange 2007 users when ActiveSync is proxied via Exchange 2013 server? I need to put CU6 to fix other bugs (duplicate
    folder) when migrating mailboxes to Exchange 2013, but I don’t have ActiveSync issues.

  98. Hello
    After install new server cu6 to root domain in multiple child domains enviroment cant move mailbox from exh 2007 because exch 2013 cu6 server only read the root domain domaincontroller controller and finished move with error because in root domain dc haven’t
    got mailbox information…
    please help.

  99. Sneff Gabor says:


    Afteer change in forestwideaffinityrequested = true to false and restart server the migration start without any problem…

  100. Mr. Exchange says:

    slow online mode "browsing" from Outlook on a Windows 7 or Windows Server 2008.. Take a look at this post:

  101. Greg Jacknow says:

    How does this play with Ex2013 SP1? Are they releasing an Post SP1 CU with similar fixes?

  102. cwastell says:

    Found an issue with the installer for CU6 if you have more than 1 ActiveSync Virtual Directory:

    Fails at step 11 of 13 Client Access role: Client Access Front End service. Solution is to remove the extra Active Sync virtual directories before installing CU6.

  103. Jonathan says:

    Installed CU6 ad it seemed to install just fine…..the only problem is it completely tanked my IIS/OWA setup, so no one could get to OWA! #Frustrated

  104. Brett B says:

    I’m having some issues post-install of the hotfix. OWA reply/calendar/new message are not working on several servers. I compared 2 servers (one working for these functions, one not) and found that :Program FilesMicrosoftExchange ServerV15ClientAccessOwaprem10.0.995.31
    is missing nearly a thousand files. My lab/test servers are working fine so I can’t test against them right now, but my thought is copying them from a "working" server may resolve this. I should be able to confirm this tomorrow after my emergency maintenance
    window tonight.

    Also noticed some services after the Hotfix install were shown as "Disabled." Leads me to believe the hotfix may bomb out without sending feedback to the user or install application. When I saw the services fail to be set back properly to Automatic start, I
    re-ran the hotfix after a reboot and it appeared to have worked for at least that portion of it – this happened on 3 out of the 6 servers (CAS/Mailbox Combined) on which I ran the hotfix.

    Has anyone else seen these issues?

  105. GpC72 says:

    I have a Exchange 2007 (where are all my mailbox) and I have installed an Exchange 2013 in Hybrid Mode….
    I’ve installed CU6….
    Now I’ve ran the script-fix BUT if I move a mailbox from 2007 to Exchange online (now the wizard is visible….) :
    Error: MigrationRecipientNotFoundException: A recipient wasn‎’t found for "xxx@yyy.zzz" on the target. Create a recipient of the appropriate type for this migration on the target and try again.
    BECAUSE Exchange 2013 don’t have created the "mail user contact"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    AND NOW??

  106. Philip Nunn says:

    Running Setup.exe /PrepareSchema etc says "Welcome to Microsoft Exchange Server 2013 Cumulative Update 5 Unattended Setup". Even after /PrepareSchema, /PrepareAD, PrepareAllDomains (all completed successfully), the Configuration partition in AD still shows
    msExchProductID 15.00.0913.022 (which is CU5). CU6 is 15.00.0995.029. When you launch the GUI setup, it correctly updates the schema though. So…unattended setup is broken. What gives?!

  107. gerard says:

    These were are my issues with installing CU6:

    1. An unexpected error has occurred and a Watson dump is being generated: A reboot is required to complete file operations on ‘{4934D1EA-BE46-48B1-8847-F1AF20E892C1}’. Reboot the machine, and then run setup again.

    This happens on nearly every Exchange 2013 update, and it does usually go away after restarting the server, I guess the only way to prevent it is to restart the server BEFORE starting setup.

    2. During the "Mailbox role: Transport service" step I got the Cannot start service MSExchangeServiceHost on computer ‘.’ error. This was due this service and it’s depency (Active Directory Topology service) being "Disabled". After changing the startup type,
    they both started fine, but this issue kept repeating in several subsequent steps. All Exchange services were being ‘restored’ to Disabled at the beginning of each step, and every time Setup tries to start MSExchangeServiceHost even though it is disabled.
    I "fixed" this by running this PowerShell script while running the CU6 setup:

    do {
    Get-Service *MSExchange* | Set-Service -StartupType Automatic
    Sleep -seconds 5
    } while ($true)

    3. Setup re-creates the DiscoveryMailbox, which I forgot to delete, so I got the usual "Couldn’t resolve the user or group " Exchange Security Groups/Discovery Management." error that apparently will never be fixed. Fixed it by deleting
    the AD-account for this mailbox, and running setup again.

    4. The "Default Frontend" receive connector had been stripped of it’s ability to relay for anonymous users, which I had configured for it to receive outbound mail from Exchange Online (we use centralized mail transport), I had to add it back.

    It is also quite annoying that:
    – setup will not resume where it left off when an error occurs, but will do several steps again that were already done.
    – setup just quits when it is ready, no message saying that it finished. Had to check the log to make sure it finished without error.

    CU6 was by far the most time consuming (wasting really) Exchange update I’ve ever installed.

  108. Peter says:

    Did you encounter any problems with IMAP after deploying CU6?
    If I use any client that uses IMAP I get "Command error. 12" on any operation (move e-mail, delete etc.).

  109. Peter R says:

    @Brent It seems that KB2997355 which includes script to fix ECP/EAC doesn’t do the trick. After updating to CU6 I cannot find RemoteDomains.xaml which is altered in the script. It doesn’t exist on any fo the Ex servers (CAS, MDB).
    Also I noticed that there are some problems with IMAP and non-outlook clients. Some of extension commands are not recognized by the server (for example – move, server returns bad command 12).

  110. Paul Wilson says:

    Installed CU6 on server1 after install all contentIndex status are unknown. Started 8pm 12/09/14.
    Using command: Get-MailboxDatabaseCopyStatus | Ft Name,contentindexstate, Contentindexerrormessage -Autosize
    I get error for all of them: "Could not find registry value of Index Status for database"
    So I checked and server1 has nothing in [HKEY_LOCAL_MACHINESOFTWAREMicrosoftExchangeServerv15SearchIndexStatus]
    Antivirus is not active, restarting the services doe’s not create keys, can not rebuild index. And even recreating the service does not create the keys.
    Trying to fudge the keys from Server 2 on SP1 does not work, I modified to the correct DB SIDS and even tried leaving the key values blank. Can find no article in this area

    So server 1 partially working but no index status, searching web I find nothing!

    Server 2 stalls on install, server 1 took 45 mins to install, exact same server/hardware but at alternate site in same domain takes 3 hours on install and fails on the transport service. And I waited 1 hour before I started install for replication in the domain
    to occur!

  111. dustin says:

    So, after being on three extended calls with MS Premier over the past two weeks all related to CU6, I am looking to avoid yet another.

    Environment is Exchange 2013 CU6 w/ IUs coexisting with Exchange 2007. Pre-CU6 mailboxes could migrate fine, Post-CU and IUs, mailboxes fail with the following error:

    Error: MigrationTransientException: The operation couldn‎’t be performed because object ‎’‎’ couldn‎’t be found on

    Is this potentially a known issue? Or, is there some specific logging I should turn up to troubleshoot?

  112. Paul Wilson says:

    Having some major Index issues, I have 2 servers. The first server after install had its content index status registry keys wiped. At the moment no matter what I do that server can not operate with indexing!
    More Info here:

  113. Philip Nunn says:

    The CU6 unattended setup seems to be broken as well. When running any of the setup.exe /prepare* cmdlets, it says "Welcome to Exchange Server cumulative update 5…" Not only that, but when you actually run the cmdlets, it doesn’t appear to properly extend
    the schema. Running the GUI setup extends it just fine. I confirmed this by checking the msExchProductID after running in unattended mode and after using the GUI (before Exchange was actually updated).

  114. Maurice says:

    Good question from Xypriz –> When can we expect to have the Set-MailboxSentItemsConfiguration cmdlet back??? Why is this command not available anymore???

  115. Jermal says:

    I have installed CU6, per request by the O365 Team. From that point forward I have faced various issues which has caused outrages for my customers. Office 365 Support are no help and directed me to work with the Product Support Team. Product Support indicates
    known bugs in my situation, although they have not been made public and wouldn’t go into further details. What they now wan’t me to do is to turn up a new Exchange 2013 Server, Download and install CU6 (again) and install it on the new server. Once installed
    and working they want me to preform a "Forklift" migration, of my databases. — I am blogging my updates on this here:

    – Jermal

  116. Andras Tudos says:

    Does anybody know what is the reason when the CU6 upgrade crashes with "Object reference not set to an instance of an object." when it is running " ‘Start-PreConfiguration -Mode ‘BuildToBuildUpgrade’ -Roles ‘LanguagePacks’,’BridgeheadRole’,’ClientAccessRole’,’UnifiedMessagingRole’,’MailboxRole’,’AdminToolsRole”
    "? This is on a mailbox server running Exchange 2013 CU4 on WS2008R2SP1 with all prerequisites. It was fine on the CAS server in the same environment and on our test boxes, but production update fails. :(

  117. Jacob Lund says:

    Is there an official fix for the OWA being broken after installing CU6 with the hotfix for Exchange 2007 coexistence. OWA can’t reply to, create, or forward messages since the hotfix KB2997209.

  118. nrsc says:

    Has anyone else noticed a large increase in logging (C:Program FilesMicrosoftExchange ServerV15Logging) since upgrading to CU 6? I have gained over 10gb of log files in the week since upgrading.

  119. Guido Leenders says:

    Please note that the install from CU 1 to CU 6 will fail when your certificate has expired. Make sure your certificates are ok before you start. We wanted to fix an expired certificate by using our SSL offloading facility to ease administrative burden,
    but it fails in step 10 (Transport service) with:

    The following error was generated when "$error.Clear();
    Install-ExchangeCertificate -services IIS -DomainController $RoleDomainController
    if ($RoleIsDatacenter -ne $true -And $RoleIsPartnerHosted -ne $true)
    Install-AuthCertificate -DomainController $RoleDomainController
    " was run: "System.Security.Cryptography.CryptographicException: The certificate is expired.
    at Microsoft.Exchange.Configuration.Tasks.Task.ThrowError(Exception exception, ErrorCategory errorCategory, Object target, String helpUrl)
    at Microsoft.Exchange.Configuration.Tasks.Task.WriteError(Exception exception, ErrorCategory category, Object target)
    at Microsoft.Exchange.Management.SystemConfigurationTasks.InstallExchangeCertificate.InternalProcessRecord()
    at Microsoft.Exchange.Configuration.Tasks.Task.b__b()
    at Microsoft.Exchange.Configuration.Tasks.Task.InvokeRetryableFunc(String funcName, Action func, Boolean terminatePipelineIfFailed)".

  120. Geary E says:

    I’m trying to run setup.exe /PrepareSchema command and it shows as Cumulative Update 5 Unattended Setup. I’ve downloaded CU6 and extracted twice, but it still shows up that way. I thought maybe this was a typo, so I went ahead and ms-Exch-Schema-Version-Pt
    still shows as 15300 (CU5) instead of 15303. Is there a mixup?

  121. princessid says:

    Problem with ManagedAvailability after CU6 implementation:

    Mailbox Transport Submission – the verification that the probe messages were successfully submitted within 5 minutes to HUB has failed. This could indicate that the mailbox submissions are taking too long or not progressing at all.

    There is more error text in the logs, it seems like a latency issue. It appears on all nodes, directly after CU6. MailboxTransport HealthSet is unhealthy.
    But, all tests are succesful, we are not experience any harm/issue. So, can we consider it as "by design" or should we take action?

  122. Matthew says:

    Do we have any update on Set-MailboxSentItemsConfiguration?
    Is this on the roadmap for a future release, are there plans for an alternative solution?

  123. Mr Wrighty says:

    My ISP has just installed this upgrade and it broke their Exchange services. Got login errors and could not connect. It has particularly affected MAC clients including Mac Mail and Outlook 2011, although Outlook 2013 is having trouble maintaining a consist
    amt connection. The Exchange services provided by my ISP have not been working since Wednesday/Thursday last week and it is still not fully functional. Well done Microsoft.

  124. Mitchell says:

    We got hit with the 2007/2013 databases failing over issue this week. Only 1 DB impacted out of 120, but it was flapping every hour or so. Had to install the Interim Update on 24 2013 servers. We only have 2 mailboxes on the 2007 server, but it doesn’t
    matter all 2013 DBs could get hit. Users on the impacted DB complained they were having to close and reopen Outlook 2013 for their Inbox to update. The update will have to be uninstalled before going to CU7. If you are on 2013 SP1 and came from 2007, skip
    CU5 and CU6, wait for CU7! (although who knows what new issues we’ll have with that!?)

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