Hyper-V RC1 is available for download

Update: 26th June 2008. Hyper-V RTM is now available. RC1 is pre-release software. 



We're getting really close to shipping Hyper-V. Today, we can announce that RC1 is available.


If you're already running RC0, the upgrade is really simple. Unlike the Beta to RC0 update, virtual network configurations and virtual machine configurations are now compatible and are migrated in-place. The only gotcha to watch out for is that saved states are not compatible, which includes online snapshots. So please make sure online snapshots are deleted and merged, and your virtual machines are shutdown cleanly before applying the update.

If you are still running Hyper-V Beta, take a look at KB949222 for more information. Although that KB was written specifically for Beta to RC0 updates, the same overall information applies for Beta to RC1.

There is one thing in particular worth mentioning about RC1 - after the feedback you gave us in RC0 that upgrading the Integration Services for Windows Server 2008 virtual machines was inconsistent with all other operating systems, we listened. Starting with RC1, all virtual machines are equal in this regard. Simply run setup.exe from vmguest.iso (Actions/Insert Integration Services Setup Disk in Virtual Machine Connection) regardless of the virtual machine operating system. Note that you still need to apply the main update to the parent partition though!

The links are here:

Windows Server 2008 x64 (Apply this to the parent partition to upgrade to RC1). More info in KB950049.

And if you are using Windows Vista for Remote Management, here's the tools you need: (KB949587)   x64 and x86

RTM is getting closer! As always, I welcome your feedback about this release.



Comments (56)

  1. Ward – there is no change in repect of legacy network adapters in RC1. You’re more likely seeing an incompatibility between RC1 and SCVMM. Rakesh has some more information on his SCVMM blog entry here: http://blogs.technet.com/rakeshm/archive/2008/05/20/scvmm-2008-beta-and-the-hyper-v-rc1-release.aspx



  2. Anonymous says:

    The fun bit in Microsoft Scotland is working with customers to discuss how Microsoft solutions could

  3. Anonymous says:

    Hyper-V RC1 업데이트가 나왔습니다. 다운로드는 여기 : http://www.microsoft.com/downloads/details.aspx?FamilyId=7EDAA89F

  4. Anonymous says:

    The RC1 release of Hyper-V ( KB950049 ) hit Windows Update yesterday. For more information on Hyper-V

  5. Anonymous says:

    The fun bit in Microsoft Scotland is working with customers to discuss how Microsoft solutions could

  6. Thomas – no, that should not be necessary. Unfortunate as it was, the breaking change was a penalty of using pre-release software and necessary to ensure support once we reach RTM.



  7. Anonymous says:

    Desi nu este o stire noua, asta spune multe despre Hyper-V! Personal, acum ceva vreme nu eram mare fan

  8. Anonymous says:

    How do you load RC1 on Server core?  It does not show up using >wmic qfe list

    with automatic updates on

  9. Robert – no, the reboot is required to ensure that the our drivers and in particular the Hypervisor can be re-launched with the latest bits. Until you do the reboot, the later drivers are not actually installed and running.



  10. Wally – you may be hitting a variation of http://blogs.technet.com/jhoward/archive/2008/03/31/hyper-v-installation-freezes-at-54-or-uninstallation-freezes-at-75.aspx in the initial update. However, not sure why it would be at 58% – 54% is what I would expect. Was that a typo?

    For the networking issue you are currently seeing, can you ne a bit more specific. Can you create virtual network switches? If so, are you saying that your VMs cannot access the network? Have you run the Integration Services setup inside the VM to get the RC1 drivers inside them?



  11. Anonymous says:

    Esta build (7100. 0. winmain_ win7rc. 090421- 1700) foi compilada na passada Terça- Feira e ao que parece já começou a ser distribuída a parceiros OEM.

  12. Anonymous says:

    The fun bit in Microsoft Scotland is working with customers to discuss how Microsoft solutions could

  13. Michael – Thanks for the info. This actually appears to be a different problem from the one I was describing. Can you possibly email me using the link at the top right of my blog some info about the processors which are in the machine itself. If you can use the vendor (I think this looks like an AMD) processor utilities to get some further ID information out, that would be hugely appreciated.



  14. Fred – the Q9450 processor itself should work. It usually comes down to a combination of full BIOS support and the correct BIOS settings. Have you also turned on NX/XD (I can’t give a simple answer to what it might be described as in the BIOS as each vendor tends to call it something different – it may be under a "Security" menu). Also, make sure you HARD power the machine off after turning on VT for it to take effect. If no luck after that, can you provide details of the motherboard and the Hypervisor launch failure error code fro the event log.



  15. Dale DU-IT says:

    If my earlier comment made it to your eyes, I now understand where and how to change the snapshot location per VM.  Also I believe that it defaults to whatever is set as the VMC directory.  So in this case if you’ve set up the top level configurations to move VHD and VMC files to a non-core (system) partition then running out of free space should never be a problem with a Hyper-V / Server Core installation.  I’m sure the RTM documentation will guide users how best to deploy but for now its ‘no pain no gain’.  As for now this Help is missing at least from what I’ve been able to not discover.

    Kudos for a great blog

  16. Barry – we’re looking at various approaches for future releases. WU for 2K8 VMs will update the guest components. It gets significantly more complex to put "down-level" operating system integration services up on WU. But thank you for the feedback.



  17. Rob – great, glad XP is resolved. I’m waiting for full confirmation but the folks that know are home for the night so I won’t get a complete answer until they’re back in the office tomorrow.

    However, this is what I did get back: IIRC, it should be as simple as unloading all the modules and then running setup.pl from the new bits.

    Maybe worth giving that a go in the meantime?



  18. Rob – it sounds like autoplay isn’t kicking in. Dismiss the "Found new hardware" dialog, and run setup.exe manually from the virtual CD/DVD device inside the VM. That should kick the installer off.

    I’m not sure about Linux – I’ve never gone through installing ICs inside Linux VMs (It’s a policy thing). I’ll find out from some folks that know more about that side of things and get back to you soon.



  19. MichaelVC. Yes, we are aware of a bug in RC1 which affects the Hypervisor from launching correctly on a small number machines. The class of machine is where there is more than one physical socket containing processors, and the processors are reporting mismatching capabilities. However, that fix will not be available until a future release. Is there anything in the system event log during machine boot which indicates a Hypervisor failure? If so, can you post back the error message for me to confirm if you are hitting the same problem.



  20. Andrew – do you by any chance have a memory.dmp file on one of the VHDs for a VM which was bug-checking 124. 124 is a hardware error, not specific to any particular type of hardware. If you do have the .dmp file, is there any chance you can email me using the link at the top so we can analyze the cause of failure? I’ll email back an FTP location to upload it to Microsoft.



  21. Hi Mark – yes, you need to upgrade the integration services to the RC1 bits so both child and parent match.



  22. Rob – glad you got it sorted. The answer I did get back was:

    1. Log in as root.

    2. Execute the following commands as root:

    a. $ rmmod netvsc storvsc vmbus

    b. $ cp /boot/grub/menu.list.bak /boot/grub/menu.lst

    3. Follow the setup instructions as detailed in the read me.



  23. Dean – you have done actionsinsert integration services setup disk from Virtual Machine Connection and run setup.exe (autoplay or manual) inside the VM?



  24. Dale – sounds like you got it. The default location isn’t any different regardless of "full" or "core" installations. Yes, we are working on documentation, and what there is available is generally in blogs and forums. Official documentation will generally be available when we reach RTM.



  25. Dave

    No, not quite.

    1. Shutdown VM

    2. Delete saved states

    3. Delete snapshots, wait for merge to complete.

    4. Install RC1 and reboot as needed

    5. Start VM

    6. Install ICs in VM by running setup.exe from vmguest.iso which is inserted into the virtual CD/DVD drive using the actions/insert integration services setup disk from Virtual Machine connection.

    Running that setup.exe updates the appropriate drivers for synthetic device support in the virtual machine, as well as the integration components such as heartbeat, shutdown etc.



  26. Murat – Can you provide some more information on the bugcheck code and the driver if you can see that information on the screen? Can you boot the VM into safe mode? What OS is running in the VM and were Integration Services previously installed, if so, the RC0 components. Feel free to drop me a mail using the email link at the top of this page.



  27. Michael – easiest way is to look at the version number of one of our drivers (eg windowssystem32drivershvboot.sys). I’m not in front of a Hyper-V machine right now, and it’s been so long since I used RC0 that I’m struggling to recall the build number <gulp> but IIRC, it was 18004. RC1 is 18010.  Beta was pre-18000 which is the build number of Windows Server 2008 RTM, and stretching my memory, it was 17119 for our bits.

    If you need a registry key, take a look at a Hyper-V enabled box, and do a search in the registry for one of the above numbers. There should be plenty of files in the registry with that number which you could equally well use for a check. We don’t have an explicit registry key as such.

    A third way would be to use WMI to query for QFEs installed on the machine eg "wmic qfe get hotfixid". Always look for the latest QFE. If 950049 is listed, you have RC1. If 949219 is installed, you have RC0 (assuming 950049 which superceeds it is not present). If neither are listed, you are on beta (Windows Server 2008 RTM). Of course, I can’t disclose future KB numbers though 🙂

    Hope that helps,



  28. Bill – the 9450 specs indicate it is VT capable, so this is more likely a problem with either the BIOS settings (maybe they get reset on a processor swap???) or BIOS support itself – latter being somewhat less likely if it runs the 6600 on the same board. If you do get the error message, please let me know.



  29. Hans Vredevoort says:

    Upgrading from RC0 to RC1 was really easy. Took me a few minutes (not counting the backup of my virtual machines beforehand).

    I am hosting my two sister’s Exchange 2007 mailboxes on my Hyper-V host. Mission critical as you could imagine : – )

  30. Robert says:

    My machine required a reboot – kinda annoying.  Is there anyway to avoid the reboot?

  31. Robert says:

    Would be nice to have a way to delete snapshots from multiple VMs all at once.  Next version?  🙂

  32. Mark Deason says:

    Updated 1, 1 to go.  Very easy, but I have one question I can’t find any info on:  Do the Integration Services on any client require upgrading to RC1?

    Thanks again for the help on the Jumbo Frame suggestion – still testing it out! 😉

  33. robr says:

    How exactly do I upgrade WinXP client integration services that were previously running RC0?  When I boot those, I get the ‘found new hardware’, I cancel that, I select install integration components and nothing really happens.  I tried rebooting the XP client to check and see if it worked, but it comes up again with the found new hardware dialog.

    I also have a question about upgrading Linux component services as the document only explains about installing it, not upgrading it (I *need* that new mouse via RDP fix).  Perhaps there is a better place for that question though which I will go look for.

  34. robr says:

    Thanks once again John, I manually ran setup and that solved the problem for my WinXP clients.  Anything you can find out about the Linux RC1 client would be appreciated.  I received an email from msftconn which says

    "Hot on the heels of the RC1 release of Hyper-V, we’ve released the RC1 compatible version of the Integration Components for Linux.

    With this update, we’ve added support for the synthetic mouse device. With this functionality, you no longer have to use the CTRL-ALT-LEFTARROW key combination to break the mouse out of the VMConnect window. This also allows the mouse to work when you access a Hyper-V host over a RDP connection."

    But when you go to the connect site and download the documentation, nothing is mentioned about  how to perform an upgrade from Linux IC RC0 and while there is this paragraph about the mouse, there’s no specifics on how to install the driver unless it just works following the rest of the instructions, but before doing that I want to make certain there aren’t a different set for performing an upgrade.

    "• NEW Mouse Support: Support for the synthetic mouse device has been added in the form of an early “preview” driver. This new mouse support allows the mouse to move in and out of the window without having to use the CTRL-ALT-LEFTARROW key command to break out."

  35. robr says:

    Solved the Linux question myself.  You really only just need to reinstall the drivers portion as far as I can tell.  I now have mouse in Linux over RDP, so for anyone else with this question, just follow this piece of the documentation:

    10. mount LinuxIC.ISO in the virtual machine.

    11. Copy the Linux integration components to the virtual machine (note rename the old linux_ic directory if you have RC0 installed). For example:

    $ mkdir /opt/linux_ic

    $ cp /mnt/cdrom/* /opt/linux_ic -R

    14. Run the following command as root:

    $ /opt/linux_ic/setup.pl drivers

    I’m not 100% sure networking is working however, I’m still working that out, but at least I have mouse :).

  36. robr says:

    Just to update, networking is in fact working, however I had to completely reconfigure seth0, my old static config was wiped out and it was set back to DHCP.  BTW, above you’ll notice I edited out some steps inbetween 11 and 14, specifically:

    /opt/linux_ic/setup.pl x2v /boot/grub/menu.lst

    That generated an error saying I wasn’t running the Xen kernel (which I was) and it appears to be unnecessary when performing an upgrade from RC0 to RC1.  I now have everything working once again, and thankfully now have mouse over RDP in Suse.  Woohoo!!

  37. Delambre says:

    "Starting with RC1, all virtual machines are equal in this regard."

    Very cool. It was very easy to migrate from RC0 to RC1.

    Thx a lot

  38. wally says:

    I did go through the artical for upgrade I wanted to go from Beat Hyper-v to RC1, when I applied the RC1 wanted to restart when the restartd it stack 3of3 58% no mater what I tried to bring the server back could not.. so i had to renistall W2k8 and applied the RC1 then installed the Hyper-V roll, when I run integration services it update everthing except network I have run integration services many time also rebooting the virtual server the VHD was from beta but with but was build with full w2k8 version..

    any suggestion…

    Thank you


  39. Tore Lervik says:

    The update from RC0 to RC1 went really smooth and the VM’s seem to behave much better.

    The problem with Attesic NIC also seems to be gone with RC1 =)

  40. Ryan Lenkersdorer says:

    Hello Again,

    So I highly doubt that you want to hear this again but it looks like a variation of the "You do not have the requested permission to complete this task. Contact the administrator of the authorization policy for the computer ‘COMPUTERNAME’" error with a new name.

    So I am running Windows Vista Business SP1 (x64) and I just installed Hyper-V RC1 on my servers (Very nice and simple install with no problems, THANK YOU) and Hyper-V RC1 Management Console on my Vista workstation. I get the following error when trying to connect to one of my servers: "Access denied. Unable to establish communication between ‘SERVERNAME’ and ‘WORKSTATIONNAME’"

    I am added to the local administrators group on the servers and it recognizes me as an admin in all other forms of remote management, just not Hyper-V. All computers are on the same domain. I have two Hyper-V servers running Server Core clustered together and I cannot access either. I can access Hyper-V on both of them using a full install of Server 2008 on a different computer.

    Any Ideas this time around?


    Ryan Lenkersdorfer

    Washington State University


  41. Thomas Goddard says:

    Please, GOD, say we don’t have to remove the virtual nics in the next release.  This is a nightmare for remote administrators…

  42. Ward Jongbloed says:

    I updated to RC1 and I’ve noticed I no longer have driver support for x64 legacy network adapters in my guests. I use the legacy adapter for deploying purposes (from SCCM), which is how I noticed in the first place (task seqeunce failed)

    Kind regards,

    Ward J

  43. DaveAdams says:

    Hi John,

    Your Beta to RC0 guide absolutely saved my skin on a critical server when that came out – I had blindly just applied to the update without any precautions!

    Anyway, that experience, which was nerve-racking to say the least, has made very wary.  Can you just clarify the steps for updating to RC1 from RC0 – particularly with regard to Integration Services for Windows Server 2008?  My understanding is this (where I have a single VM and single parent);

    1. Install RC1 update on guest virtual machine

    2. Shutdown VM

    3. Delete saved states for VM

    4. Install RC1 on parent

    5. Reboot

    6. Start VM

    All done?  What about Integration Services for Windows Server 2008 – what do I need to do there, what is it’s function (sorry, but I’m still pretty new to VM’s)…


    3. Delete snapshots

  44. MichaelVC says:

    Hey John,

    I recently rebuilt my machine and found that beta version of Hyper=V worked without a problem.  The after I downloaded the RC1 code and installed it, I am being told that Hyper-V failed to launch.  I am seeing this as a problem on a lot of the forums.  Anything you have heard about?

    Thanks in advance.

  45. Michael Myers says:

    How can I confirm the version of Hyper-V that I am running?  e.g. what’s the registry key that I should be looking for?

  46. Andrew Teece says:

    ARRRGGGGGGHHHHHHH. It didn’t go smoothly at all!

    The RC1 got deployed by our companies approve-all WSUS settings. This ment that some of the VMs got the new integration componenets b4 the host, but others didnt.

    Then, when things rebooted automatically, all hell broke loose over night!

    Now, I havent read anywhere that you MUST install the integration componenets into W2k8 x64 guests before doing so on the host, but in my case the w2k8 guests without RC1 ICs got BSODs on bootup 0x00000124 to be precise. From a little googling this seems to relate to NVidia graphics cards. So I booted the guest VM into safe mode. Removed the VMBus graphics card. Rebooted into normal mode and could then install the new integration componenets from disk. PHEW

    Just thought I would share my "fix" incase anyone else has BSODing guests

  47. MichaelVC says:


    Thank you for the response – it is refreshing to know that it is a known bug – when you say future release do you mean by RTM 🙂

    The error code that I am recieviing is as follows:

    Hyper-V launch failed; Processor 0x2 does not provide the features necessary to run Hyper-V (leaf 0x80000001, register 0x1: features needed 0x34d, features supported 0x351).

    + System

     – Provider

      [ Name]  Microsoft-Windows-Hyper-V-Hypervisor

      [ Guid]  {52fc89f8-995e-434c-a91e-199986449890}

      EventID 48

      Version 0

      Level 2

      Task 0

      Opcode 0

      Keywords 0x8000000000000000

     – TimeCreated

      [ SystemTime]  2008-05-28T18:12:13.390Z

      EventRecordID 4748


     – Execution

      [ ProcessID]  4

      [ ThreadID]  8

      Channel System

      Computer WRK-MVC

     – Security

      [ UserID]  S-1-5-18

    – EventData

     CPU 0x2

     Leaf 0x80000001

     Register 0x1

     FeaturesNeeded 0x34d

     FeaturesSupported 0x351

    I am running RC1 – the version is 6.0.6001.18010.

  48. Deano says:

    I upgraded from the Beta to RC1 this morning and now have a problem with my existing VM guests.

    After re adding the VM win 2008 server and run the Integrations setup I am still unable to connect to my virtual network and the the VMBus Network driver is giving me a code 10 in device manager.

    Anyone else have this problem or a suggestion on how to fix it ?

  49. Dale Unroe says:

    Found out  the hard way on a server core install of Hyper-V that snapshot data files are not put on the same partition as the vhd files are located.  When I deleted the snapshots in the Hyper-V manager they were not deleted from the C: partition which was so full that I couldn’t run either virtual machine long enough to accomplish shuting them down.  So what then ensued was my huge 40 GB partition for server core had 0% free space, couldn’t remove the snapshots without powering down the virtual machines, and couldn’t power down the virtual machines.  I had to remotely browse to the hidden system share c$ in order to get to the physical snapshot to delete.  Unfortunately that damaged the VMC such that I had to create a new one; however, that broke the NIC and/or SID relationship of the virtual machine with the DC and I now have to log in as local admin to remove and then rejoin network.  ughh!  One down one to go.

    Can shapshots please be located on a seperate partition from Server Core?

    Thanks in Advance – Dale

  50. Bill Kastner says:

    I am having a similar issue with a new Intel Quad Core Q9450 processor.

    I had a Dual Core E6600 and Hyper-V RC0 & RC1 work great, but I swapped it out for the Q9450 and Hyper-V hypervisor fails to load as it reports my CPU does not support it.

    I reloaded W2K8 with Hyper-V RC0 and RC1 and had no luck no with either.

    Unfortunately, I don’t have the exact error code as I rebuilt the server with my E6600 so I could get my servers back up and running for a project.

  51. Bill Kastner says:

    I confirmed BIOS settings, flashed to latest BIOS, re-confrmed settings, all with the same result. Removing the 9450 and plugging in the 6600 back in fixes the issue instantly.

    I will try and swap out processors again over the next couple of days and grab event logs.



  52. Gary Foley says:

    Can you explain how to install rc1 with server core?

  53. Barry says:

    I’m sure it’s been asked before, but why have the various guest components not been available on Windows Update?  If the interface between guest and host really looks like virtual hardware, it should be pretty easy.

    it would seem to me a very easy way to address the update process.  Granted, it would probably require a looser coupling of the host and guest componenets, but it sure would make things easier on those of us with multiple guests.

  54. Murat Eraydin says:

    BSOD after importing VMs from RC0!?

    After importing RC0 VMs click start and BSOD! is this a known issue?

  55. Fred Oliveira says:

    I seem to be having a similar problem to Bill Kastner above; ie I have a Q9450 that Hyper-V says doesn’t have the vmx capability.  I have verified that I have the latest BIOS and the VT is turned on. Any help for this?

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