VSS Error: Couldn’t take snapshot. The shadow copy provider had an unexpected error while trying to process the specified operation

Possible causes for this error include:

  • VSS cannot be used on mapped network drives or network shares.
  • Shadow storage on the source drives is not configured or not large enough. The shadow storage size can be checked and manually changed through an elevated command prompt or PowerShell:

To check the current limit set:

vssadmin list shadowstorage

To change the limit:

vssadmin Resize ShadowStorage /For=X: /On=X: /Maxsize=XX%

Example Usages:
vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=900MB
vssadmin Resize ShadowStorage /For=C: /On=D: /MaxSize=UNBOUNDED
vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=20%

  • Microsoft's VSS is only able to perform one snapshot at a time. If a snapshot is already in progress when your backup job starts, then the backup job could fail. Stopping and restarting the Volume Shadow Copy service can resolve this problem. To do this, open an elevated command prompt or PowerShell window and run the following commands:
net stop vss
net start vss

If restarting the VSS service with the 'net stop vss & net start vss' shown above does not resolve the issue, a server reboot has also been known to clean up the snapshot manager correctly.

vssadmin list writers

This will provide an list of all VSS writers on your PC. You want to check the Last Error and State items.

  1. The value of Last Error should always be No Error, if the status is different you have a problem writer.
  2. The value of State should be show [1] Stable.
  3. A simple reboot of the PC may resolve this problem. If the issue continues after a reboot, it could indicate a larger issue within the PC.
  • Event logs: Examine your application and system event logs focusing on the error events created by VolSnap and VSS at the time of failure.
  • Check for 3rd party VSS providers. From an elevated command prompt or PowerShell:
vssadmin list providers

If you have any VSS providers listed other than Microsoft, you should disable them.