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Starting VM in Hyper-V while Server Backup is in progress

sglee used Ask the Experts™
Windows Server BackupAVHDX FilesHyperV ManagerHi,

 I have a Virtual Machine running SBS2011 that is turned off while Windows Server Backup is still in progress.
 I see  .avhdx files created for the downed VM obviously because the backup is still in progress.
 Is it ok to start the VM now before the backup is finished? What risk is there if I try to start the VM at this point in stead of waiting until the backup job is finished?

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Top Expert 2016

yes it is always usable when a backup is running.
The backup has created a snapshot and will backup the .vhd while any changes will be written to tha .avhdx
once the backup is finished it will delete the .avdx and merge the changes with the .vhdx


Failed to start VMWhen I tried to start the VM, I get the following message.
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Looks like it's locked.

You'll need to wait until finished or cancelled.


The Backup is at 92% now. I will just wait and restart Hyper-V server.


After Windows Server Backup was completed, I rebooted Hyper-V Server and I was able to start the VM successfully.

Had i cancelled the backup job (before job w as finished), would .avhdx files have been automatically removed from Virtual Hard Disk folder?
Top Expert 2016

probably not but from powershell you can remove them

get-vm | remove-vmsnapshot

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