The latest Hyper-V service packs, updates, and hotfixes for Windows Server 2012 are listed here in chronological
order with most recent updates placed at the top.
Applies To: Windows Server 2012
Note: These updates and hotfixes can help avoid some known issues and may save you a support call.
A hotfix is intended to correct only the problem that is described in the article. You should not apply the
hotfix if you have not seen the symptoms.
Note: A catch 22, do you install it to try preventing the problem from occurring or do you only install it
if you see the problem and have an outage?
Note: Some updates are required only under certain circumstances, as noted in the table.
Note: On this
link you can find a tool to help you identify which hotfixes and updates are installed and missing:
14 Apr 14
KB 2937634: Hyper-V Host Unable To Reconnect To WS2012 SOFS After Unplanned Failover
Yes, if used with Scale-Out File Server
10 Apr 14
VM Network Fails If “Minimum Bandwidth Weight” Is Enabled On WS2012 Hyper-V
KB 2908783: Data Corruption Occurs On iSCSI LUNs In Windows
9 Apr 14
KB 2928678: Windows RT, Windows 8, and Windows Server 2012 update rollup: March 2014
8 Apr 14
KB 2908783: Data corruption occurs on iSCSI LUNs in Windows
Included in KB928678
14 Jan 14
KB 2870270 Update that improves cloud service provider resiliency in Windows Server 2012
24 Dec 13
KB 2894485: Cross-page memory read or write operation crashes virtual machine that is running on a 64-bit Windows 8-based or Windows
Server 2012-based Hyper-V host
23 Dec 13
KB 2878635 Update is available that improves the resiliency of the cloud service provider in Windows Server 2012: December 2013
10 Dec 13
KB 2894032: Clustered virtual machine cannot access LUNs over a Synthetic Fibre Channel after you perform live migration on Windows Server 2012-based
Yes, if you run in a Virtual Fibre Channel environment
29 Nov 13
KB 2838043: Can't access a resource that is hosted on a Windows 8 or Windows Server 2012-based failover cluster
Yes. Not directly Hyper-V related, but updates a number of Failover Clustering-related binaries
30 Sep 13
Loss of consistency with IDE-attached virtual hard disks when a Hyper-V host server experiences an unplanned restart
21 Aug 13
KB 2779768: Windows 8 and Windows Server 2012
cumulative update: December 2012
Yes, install on all Hyper-V hosts and supporting storage servers. Fixes a number of issues including:
16 Aug 13
Windows RT, Windows 8, and Windows Server 2012
update rollup: July 2013
this update rollup package includes performance and reliability improvements
13 Aug 13
KB 2803748: Failover Cluster Management snap-in crashes after you install update 2750149 on a Windows Server 2012-based failover cluster
Yes, if KB 2750149 is installed (KB 2750149 is available via Windows Update)
12 Jul 13
KB 2822241: Windows 8 and Windows Server 2012
cumulative update: April 2013
Yes, install on all Hyper-V hosts and supporting storage servers. Fixes a number of issues
9 Jul 13
Windows 8 and Windows Server 2012 update rollup: November 2012
Yes, install on all Hyper-V hosts and supporting storage servers. Fixes a number of issues.
Updates IC Components!
6.2.9200.16433 (2008 and later guests)
6.2.9200.16384 (2003 and XP guests)
KB 2854362: Vmms.exe processes freeze on certain nodes in a Windows Server 2012-based Hyper-V failover cluster
Yes, if Hyper-V hosts are clustered and virtual machines are stored on scale out fileserver.
KB 2840681: Computer does not shut down after you remove a virtual switch in Windows Server 2012
Yes, if using Virtual Machine Queue (VMQ) with a network team
KB 2851998: "The last backup did not complete successfully" error message when you back up a Windows 8 system
Yes. Not directly Hyper-V related, but updates the Volume Shadow Copy Service volume snapshot driver, which could improve backup reliability
5 Jul 13
KB 2836988: Windows 8 and Windows Server 2012
update rollup: May 2013
13 Jun 13
KB 2844296: Shared Nothing Live Migration fails when you try to migrate a virtual machine to a destination server in Windows Server 2012
Yes, install on all Hyper-V hosts using Shared Nothing Live Migration
12 Jun 13
KB 2838988: You cannot manage permissions or create virtual machines on a file share by using System Center 2012 SP1 VMM in Windows Server 2012
Yes, if using a Windows Server 2012 file server to connect to SAN/NAS storage and then serving up SMB3 storage to separate Hyper-V hosts
KB 2832478: Virtual machines crash or take a long time to complete the shutdown process on a Windows Server 2012-based host computer
Yes. Prevents an issue that can cause a long shutdown process and/or a virtual machine crash
KB 2834026: "0x00000050" Stop error when you try to create a virtual machine or copy a VHD or VHDX file to a SMB share in Windows Server 2012
Yes, install on all Hyper-V hosts to prevent a system crash when VHD or VHDX files are stored or copied to a remote SMB share
11 Jun 13
KB 2845533: Windows RT, Windows 8, and Windows Server 2012 update rollup: June 2013
Yes. Not directly Hyper-V related, but updates the Volume Shadow Copy Service binaries, which could improve backup reliability.
15 May 13
KB 2836402: You cannot add VHD files to Hyper-V virtual machines in Windows Server 2012
Yes, to correct an issue that could prevent the addition of VHDs to virtual machines under special circumstances
31 May 13
KB 2811660: Windows 8 and Windows Server 2012 update rollup: March 2013
29 May 13
KB 2795944: Windows 8 and Windows Server 2012
update rollup: February 2013
Yes, includes a number of storage-related (MPIO, NTFS) and network-related fixes
24 May 13
KB 2806542: "0x000000D1" Stop error on a virtual machine in Windows Server 2012
Yes, this fix prevents a crash that sometimes happens when using an SR-IOV network adapter
KB 2809117: Add-TargetPortToMaskingSet PowerShell command fails in Windows Server 2012
Yes, but this update applies to Windows Server 2012 file servers / storage servers supporting a Hyper-V environment
KB 2807654: "0x000000C2" Stop error when you try to back up a data deduplication-enabled volume in Windows 8 or Windows Server 2012
Yes, install on all Hyper-V hosts and supporting storage servers to prevent a crash during backup when using a deduplication-enabled volume
KB 2825135: You cannot perform an online backup operation by using Windows Server Backup in Windows Server 2012
Yes, if using Windows Azure Online Backup
KB 2823956: You cannot connect to a database stored in Windows Azure SQL Database in Windows Server 2012 (sic)
Yes, if using a Windows Azure SQL Database with virtual machines running on Windows Server 2012
6 May 13
KB 2756872: Windows 8 Client and Windows Server 2012 General Availability Update Rollup
Yes, install on all Hyper-V hosts and supporting storage servers. Fixes a number of networking-related issues in Windows Server 2012 RTM
9 Apr 13
KB 2823958: Virtual switch extension cannot send packets separately through every individual network adapter in Windows Server 2012
Yes, if using virtual switch extensions with the intention of sending packets through every network adapter
KB 2823643: Virtual machines freeze at the "Stopping" state after you shut down the virtual machines in Windows Server 2012
Yes if clustering VMs with high network load
13 Mar 13
KB 2795531: You cannot log on to a virtual machine that is running Windows 8 or Windows Server 2012 in a VDI environment
Yes, if using Hyper-V in a VDI or Remote Desktop Virtualization Host scenario with Windows 8 or Windows Server 2012 as virtual machines
31 Jan 13
KB 2770440: Poor performance when you enable RemoteFX in Hyper-V on a Windows Server 2012-based computer that uses AMD processors
Yes, if hosting a VDI platform on Hyper-V and using AMD processors
9 Jan 13
KB 2785638: You cannot use the Cisco SR-IOV network adapter on a virtual machine in Windows Server 2012
Yes, if you use a SR-IOV network adapter with virtual function (VF) capability and you find that the VF is not available on restart of the VM
Avoid data corruption with WS2012 Hyper-V cluster connected to a SAN! This bug with ODX and NTFS has caused a lot of pain for me and my team over the past week. Virtual machine files become corrupted during a live migration using ODX. It took down a domain controller and two customer environments. Initial recommendation from MS was to disable ODX. There has been two hotfixes released. Not very trusting of them yet, we opted to disable ODX for now.
We need to update this list, here is another hotfix for WS2012 Hyper-V, "0x000000D1" Stop error on a virtual machine in Windows Server 2012
I totally agree with AustinB.
The mentioned kb2796995 is CRITICAL, the bug causes huge problems.
At the moment it isn't mentioned in the 2012 Failover Cluster fix list either (and it should)
ArdenW edited Revision 10. Comment: Corrected a KB2785638.
Please update the list with KB2848344 (which superseeds KB2838669).
Thanks, Roland. I've updated the article as per your suggestion.
Here is another one not in your list: KB2840681 support.microsoft.com/.../2840681
Computer does not shut down after you remove a virtual switch in Windows Server 2012
Very Cool Script to Check for all Updates and download them as needed.