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Description: There are too many existing backup snapshots on virtual machine

  • November 20, 2025
  • 2 replies
  • 30 views

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I am receiving the following error in the backup of a Hyper-V VM

Error code: [91:148]

Description: There are too many existing backup snapshots on virtual machine [ServerName]. Backup snapshots are being cleaned up, but manual intervention may be required to ensure that all snapshots are removed. This may indicate that the storage is unable to keep up with the I/O activity of the virtual machine during a backup.
Source: cs0003, Process: JobManager

When I look in Hyper-V Manager, I see no checkpoints for this server, so I’m unsure how to resolve this.  I assume it’s possible it may resolve itself over time, but this has come up the last 2 backup cycles.

 

2 replies

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​Hi ​@jwood 

Good day!

Have a look in the VM’s storage folder to see if any AVHDX files are still there.

If you find any, it’s best to get Microsoft involved to help merge and clean them up safely.
 

https://learn.microsoft.com/en-us/troubleshoot/windows-server/virtualization/merge-checkpoints-with-many-differencing-disks
https://learn.microsoft.com/en-us/answers/questions/1475008/cluster-hyperv-a-lot-of-avhdx-files-unable-to-merg

Regards,

Sureshkumar S

 


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  • Author
  • Bit
  • November 21, 2025

Yeah, there’s a bunch of files in there.

 

So for clarification, it sounds like the VM IS backing up, it’s just throwing errors for a potential issue, is that right?