Exchange 2013 CU8 Released

Exchange 2013 CU8 has been released to the Microsoft download centre!  Exchange 2013 has a different servicing strategy than Exchange 2007/2010 and utilises Cumulative Updates (CUs) rather than the Rollup Updates (RU/UR) which were used previously.    CUs are a complete installation of Exchange 2013 and can be used to install a fresh server or to update a previously installed one.  Exchange 2013 SP1 was in effect CU4, and CU8 is the fourth post SP1 release.  CU8 contains AD DS schema changes so please test and plan accordingly!

Update 19-3-2015 Removed line about AD schema changes.  According to this, there are no new schema changes present in CU8.  If upgrading from CU6 or older then AD schema changes will still need to be applied to update to the CU7/CU8 level.

Update 19-3-2015 Added more detail for CU8 Public Folder scale increases

Update 25-3-2015 Please see an emerging issue with ActiveSync after deploying Exchange 2010 SP3 RU9 or Exchange 2013 RU8.

Exchange 2013 CU8 Download

This is build 15.00.1076.009 of Exchange 2013 and the update is helpfully named Exchange2013-x64-cu8.exe.  Which is a great improvement over the initial CUs that all had the same file name!  Details for the release are contained in KB3030080.


Updates Of Particular Note

The modern public folder work continues with Calendar and Contact Modern Public Folders favourites added in Outlook are now accessible in OWA.  In addition Batch Migration of Public Folders to 2013 improves migration throughput and PF migration experience.  Note that this requires at least Exchange 2010 SP3 RU8 or Exchange 2007 SP3 RU15 on the legacy Exchange versions to allow the multiple migration streams.

In terms of increasing modern Public Folder throughput, CU8 has again increased the limits.  CU7 previously provided support for Public Folder Hierarchies in Exchange Server 2013 which contain 250,000 public folders.  These limits have been greatly increased with CU8.  Note though that there are differences in the amount of Public Folders that can be migrated, compared to the number that are supported once public folders are on Exchange 2013.

With CU8 Exchange 2013 now supports migrating up to 500,000 public folders.  Once the migration has been completed, or for net new Exchange 213 deployments, CU8 supports up to 1,000,000 public folders.   Note that a single public folder mailbox is still limited to no more than 100,000 public folders.  This includes active and folders being aged out.  The limits for Exchange 2013 Public Folders article is available on TechNet. 

ActiveSync devices can now be automatically reconfigured when moving to Office 365 as long as the client supports HTTP 451 redirects.

  • KB 3011579 The issue with Enterprise Vault which is discussed in  KB 3011579 is addressed in CU8.
  • 3045301 SMTP is not transported over TLS 1.1 or TLS 1.2 protocol in an Exchange Server 2013 environment
  • 3032153 Recurring events in Calendar over DST are not adjusted on all ActiveSync devices in all Exchange Server environments
  • 2986941 "An Active Directory error 0x51 occurred" error when you run the "Setup /PrepareAD" command from a DC in Exchange 2013


Issues Resolved

  • 3045301 SMTP is not transported over TLS 1.1 or TLS 1.2 protocol in an Exchange Server 2013 environment
  • 3040681 MapiExceptionTimeout error during a hierarchy synchronization process of multiple public folders in Exchange Server 2013
  • 3037417 Outlook cannot download an OAB file in an Exchange Server 2013 environment that mixes Exchange Server 2010
  • 3037291 Can't add members to Outlook contact group by using MAPI over HTTP
  • 3036952 Mailbox quota warning messages are not sent out after you migrate from Exchange Server 2010 to Exchange Server 2013
  • 3036374 Incorrect NDR size limit message is displayed for German localization in an Exchange Server 2013 environment
  • 3036365 "The specified address is not recognized or does not exist" error message in an Exchange Server 2013 environment
  • 3032153 Recurring events in Calendar over DST are not adjusted on all ActiveSync devices in all Exchange Server environments
  • 3031133 Default folders are duplicated after you migrate mailboxes to Exchange Server 2013
  • 3031069 Mails are spoofed in Office 365 or in an Exchange Server 2013 environment
  • 3030629 Outlook cannot open a shared folder on which a group you attend has the Reviewer permission in Exchange Server 2013
  • 3018518 Garbled text in the Japanese "From" field in a forwarded DBCS message
  • 3016440 Public folder mailbox quarantined
  • 3012266 Update to increase availability address spaces to 200 in Exchange Server 2013
  • 3011579 SaveChanges fails and generates a MAPI_E_NOT_FOUND error message on a large message body in Exchange 2013 CU6
  • 3006861 "The SMTP address has no mailbox associated with it" error when you access a user's mailbox by using EWS application
  • 3003974 Improved support for MSG files in an Exchange Server 2013 environment where OPENTEXT products are used
  • 2988060 Cannot see the auditing results for an HttpModule-based extension for MAPI over HTTP protocol in Exchange Server 2013
  • 2986941 "An Active Directory error 0x51 occurred" error when you run the "Setup /PrepareAD" command from a DC in Exchange 2013
  • 2961741 Exchange Server 2013 delegated setup fails when the setup account is a member of Domain Admins


There is a known issue with this update.  After you install this update in your environment where the DST update for Chile and Mexico is applied, the calendar items are shifted incorrectly. To work around this issue, see KB3048372 Exchange Calendar items are shifted incorrectly when some Windows DST updates are applied. 


Some Items For Consideration

As with previous CUs, CU8 follows the new servicing paradigm which was previously discussed on the blog.  The CU8 package can be used to perform a new installation, or to upgrade an existing Exchange Server 2013 installation to CU8.  You do not need to install Cumulative Update 1 or 2 for Exchange Server 2013 when you are installing CU8.  Cumulative Updates are well, cumulative.  What else can I say…


  • After you install this cumulative update package, you cannot uninstall the cumulative update package to revert to an earlier version of Exchange 2013. If you uninstall this cumulative update package, Exchange 2013 is removed from the server.
  • Ensure that you consult with all 3rd party vendors which exist as part of your messaging environment.  This includes archive, mobility and management services.
  • Ensure that you do not forget to install this update on management servers, jump servers/workstations and application servers where the management tools were installed for an application.  FIM and 3rd party user provisioning solutions are examples of the latter. 
  • Disable file system antivirus prior to installing.
  • Once server has been restarted, re-enable file system antivirus.
  • Note that customised configuration files are overwritten on installation.  Make sure you have any changes fully documented!
  • CU8 contains AD Schema updates – please test and plan accordingly!


Please enjoy the update responsibly!

What do I mean by that?  Well, you need to ensure that you are fully informed about the caveats with the CU  and are aware of all of the changes that it will make within your environment.  Additionally you will need to test the CU your lab which is representative of your production environment.




Comments (21)
  1. anonymouscommenter says:

    Trying to find detailed installation instructions, the basic Cumulative Update instructions do not detail schema updates.

  2. FrancWest says:

    The link to doesn’t work. Page doesn’t exist.

  3. anonymouscommenter says:

    I just updated to CU8 on an on-premise single exchange server environment, spent 4 hours with Tier 2 Tech support at Microsoft, the tech spent the weekend recreating my environment and was unsuccessful in configuring the public calendars and public rolodex’s
    we have in our public folders. It was determined as of yesterday when I heard the news from Microsoft Support, that the info above is not accurate. Here is the website which lists the actual updates included in CU8:

    No where in the list does it state that mail enabled public calendars and public contacts are assessable over OWA.

    Microsoft Support then refunded my the $530 for support and apologized for the false info Microsoft Released regarding the FAQ’s of CU8. They are escalating their findings to the Exchange developers to follow up on why these were not included as announced and
    published prior to CU8’s release.

  4. Franc – that link appears to be working for me right now. Can you retry please.


  5. Brian,

    To ensure I understand you correctly, Is the issue that you do not see them in OWA at all?

    Where are the public folders located? Exchange 2010 or 2013.

    I’ll follow up to see what I can find.


  6. anonymouscommenter says:

    @Roderick: indeed it works now, after I mentioned it also on the Exchange team blog, they fixed it. However, I must say that the information in the article is very minimal to say the least. It doesn’t get into detail.

  7. anonymouscommenter says:

    I also can’t see Calendars in Public Folders in OWA after installing CU8. In my lab, I get as far as the "Add public folder" dialog in OWA, and when I highlight a calendar it says "Only mail public folders can be added to Favorites."

  8. anonymouscommenter says:

    Rhoderick, The there is only one exchange server on premise and it’s 2013 Standard. We have several calendars published in our public folders and none of them are assessable in OWA after adding them are Outlook Favorites. When you try to add them to your
    favorites in OWA, it states only mail public folders can be added to favorites. This went to Tier 2 Support at Microsoft, the tech setup a demo site on his side over this past weekend and reported to me Monday that it is confirmed that CU8 does not fix mail
    enabled calendars and contacts in CU8. And then refunded me my support fees and sent me the link to the actual updates released by CU8 (which I posted in my first blog above). And no where does it state in kb3030080 that the fixes in CU8 included public calendars
    and contacts in OWA. My Microsoft Support Case is: 115031912538286

  9. anonymouscommenter says:

    In addition Rhoderick, I have search the web up and down and do not find any Microsoft FAQ or Technet article on how to configure mail enabled public folder calendars and contacts to OWA after they’ve been added to the favorites within Outlook. I imagine
    this may be due the idea that it was so simple to add there was no reason to create a document that specifically states the steps. Either that, or it is still not possible. Microsoft is usually pretty good at sending information out like this when they’ve
    added new functionality to a major system such as Exchange.

  10. anonymouscommenter says:

    There was a comment on a post on the Exchange team’s blog (
    that explains how this works. You don’t add them the way you do other public folders. Instead, you go to the appropriate tab in OWA (after adding them to the Favorites in Outlook) and they’re now listed. I’ve found the whole Modern Public Folders in OWA experience
    to be a very strange beast and surprisingly unintuitive.

  11. Great to see you guys are burning the midnight oil to get Exchange 2013 improved before the release of the next full version :). Good job on making the modern PFs available in OWA and on for batch migration for PFs

  12. anonymouscommenter says:

    Rhoderick, I’m a little confused about your statement regarding the AD Schema Update. As you mentioned there are no Scheam Changes within CU8 and therefore no AD Prep is required.
    On the other hand there are a couple of AD Schema Changes in CU6 and CU7.
    So, if I’m a customer upgrading from CU5 directly to CU8 there are indeed Schema Changes and therefore a Schema Upgrade must be included in CU8 in regard to Microsoft statement that each CU can be installed independently of earlier CUs.
    Can you please clarify this in your article.
    Thanks in advance

  13. anonymouscommenter says:

    Dana, thank you for explaining this. After installing CU8 last night I spent a better part of the day trying to figure out how to add a public folder containing calendar items into OWA using some test accounts.
    Let’s just call the CU8 a good attempt at PF availability in OWA, but let’s admit that from the user perspective it still needs a lot of work. Setting up favorites folder in desktop Outlook before you can see it on the web can only be considered a workaround
    at this time. We should be able to administer favorites from the OWA. 2013 OWA is excellent and I am surprised how much users actually use it.

  14. There is a post pending on the OWA feature, I’ll publish it early next week.

    Brian – the KB covers the fixes, and the addition of the feature was on the Exchange team blog. Features are not normally found in the KB.

    Michael – Correct. No new AD DS schema changes in this CU. If installing from scratch or from CU4 then there will be changes. The schema modifications are covered in the previous posts.


  15. anonymouscommenter says:

    Great – can’t wait for a new post. Please mention how to modify/administer user’s Favorites folder from a server side. We run into some accounts that have unremovable "favorites" that can’t be seen in desktop Outlook.

  16. anonymouscommenter says:

    The Exchange team have been working very hard to develop the feature set of modern public folders. Exchange

  17. anonymouscommenter says:

    After updating to CU8, some users on Outlook 2007 clients can no longer open Public Folders. They get the following: Your profile is not configured. (/o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers…

    Worked fine on Exchange 2013 SP1

  18. What us the exact outlook build string?


  19. anonymouscommenter says:

    In a previous Exchange 2010 post we discussed a scenario where users were delegated the capability to

  20. anonymouscommenter says:

    I am trying to update all of our servers to CU8. Many of the installs are failing. I have one in particular that is getting the following error:
    [ERROR] Unable to remove product with code 4934d1ea-be46-48b1-8847-f1af20e892c1. Fatal error during installation. Error code is 1603. Last error reported by the MSI package is ‘The installer has encountered an unexpected error installing this package. This
    may indicate a problem with this package. The error code is 2502. ‘.

    I have copied the update files several times and still cannot get the install to work. Any suggestions?


  21. xtx says:

    Hi Team

    Casually someone have the CU8 Exchange2013-x64-cu8.exe, I have some issue to Install CU21 on one mailbox on DAG, requiren CU8 files to continue

    I would appreciate if someone had it, could you share it with me


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