Hyper-V VM’s Won’t Start After October 2023 Windows Updates

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This post was originally published on November 5, 2023
The latest update to this post was made 6 months ago.

Hyper-V Image/LogoIssue

After installation of Windows Updates (Oct 2023) stand-alone, random Hyper-V VM’s fail to start with error:

  • Synthetic SCSI Controller (ID): failed to power on with error ‘incorrect function’
  • Attachment <filename.vhdx> failed to open because of error ‘incorrect function’

Event log on host hypervisor may show:

  • Error 12010 Hyper-V Worker (‘VMNAME‘ Synthetic SCSI Controller (Instance ID <GUID>): Failed to Power on with Error ‘Incorrect function.’ (0x80070001). (Virtual machine ID <GUID>)  –AND/OR
  • Error 12140 Hyper-V Synthstor: ‘VMNAME‘: Attachment ‘C:\Hyper-V\VMNAME\Virtual Hard Disks\FILENAME.vhdx’ failed to open because of error: ‘Incorrect function.’ (7864368). (Virtual machine ID <GUID>)

Note: Windows Server 2019 and 2022 running Hyper-V seem to be the primarily affected HOST server O/S.

Possible Resolutions

  • Uninstall the updates for Oct 2023, specifically KB5031364 and restart.  This would be considered the official fix (for now).  -OR-

  • Rename the affected .VHDx file(s).  Visit the folder with your virtual disks in it.  Rename the .VHDX file to something different from what is now.  Visit the Hyper-V VM settings menu, under SCSI controller ‘browse’ to the newly renamed file.  Apply changes and see if the VM will start.  -OR-

  • Delete the .MRT (modifiable region table) and .RCT (resilient change tracking) file(s) in the virtual hard disks folder of the affected VM.  These files are typically present if you use a backup solution, such as Microsoft Data Protection Manager (DPM).  This is the quickest and easiest fix and doesn’t require re-starting your host VM server.

Looking Forward

A fix is expected to be released in the November 2023 updates, although this is not 100% guaranteed as of the writing of this post.

Tags: #microsoft #patchtuesday #hyperv #vms #vm #blogencounters


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