Important Hyper-V Fixes Included in KB 2855336 (Virtualized Active Directory corruption (bug check c00002e2) and vmms process hang)

The July Windows Server 2012/Windows 8 update (KB2855336) contains two fixes for Hyper-V scenarios that are likely to be important to a number of customers.


Both of these updates are included in the rollup KB2855336.


KB2853952 – Loss of consistency with IDE-attached virtual hard disks when a Windows Server 2012-based Hyper-V host server experiences an unplanned restart (renamed from Active Directory database becomes corrupted when a Windows Server 2012-based Hyper-V host server crashes)

This issue effects virtualized active directory servers – in the event that the host crashes or looses power the active directory instance may become corrupted.  If this occurs on startup active directory will blue screen/bug check the virtual machine with an error of  “c00002e2 Directory Services could not start because of the following error:  %hs  Error Status: 0x%x.  Please shutdown this system and reboot into Directory Services Restore Mode, check the event log for more detailed information.”.  There may be additional roles or applications impacted by this issue as the underlying cause is that when a guest operating system requests the Hyper-V server to disable disk caching the wrong error is returned making the guest operating system believe that caching has been disabled when it has not.

This update should be installed on the Hyper-V host.

KB2854362 – Vmms.exe processes freeze on certain nodes in a Windows Server 2012-based Hyper-V failover cluster

This issue effects clustered Hyper-V servers with virtual machines hosted on a scale-out file server cluster.  In the event of a node failure that results in VM’s being failed over and brought online on other nodes the VMMS process on those nodes may freeze resulting in VM’s that remain in the offline state.

This update should be installed on all of the Hyper-V hosts within a cluster.


-Taylor Brown
-Program Manager, Hyper-V

Comments (1)

  1. Robert Jones says:

    Nice article.   I have a question on updates.

    I have HV core on a R610 dell server.  I recently had an issue on a guest os that runs a sybase database.

    When I attempted to update the program to the next version I kept getting this I/O error and it would fail.

    Well it could be a bug in the programs update or it could be a problem with the guest OS (server 2012).  So I rebooted the guest OS and tried to update the sysbase program.  Same error.  

    So then I rebooted the entire server with all the guest OS. Then I got back in the guest 2012 OS and tried to patch the syybase app and vialo it worked! no more errors.

    But that leads me to think there is something wrong with Microsoft HV for it to be able to affect the GUEST os.

    My trust has fallen.   On the reboot I noticed it installed some new server core patches.  One of those patches was KB2855336 and some others that are dated back to 2013.   So I'm thinking why did those not get installed last month?   Why now?  

    I need a way to compare what patches I have on core to what I could have.   It seems it skipped some.