Errors Removing snapshots after backup

[SamDLC]

Today i started noticing that one of my backup jobs was sending warnings. It looks that Veeam was not able to remove the snapshot and now my VM is runnin on a snapshot disk.
This is the error I am receiving.
"Removing snapshot RemoveSnapshot failed, snapshotRef "80-snapshot-15", timeout "3600000" Unable to access file <unspecified filename> since it is locked Veeam Backup will attempt to remove snapshot during the next job cycle, but you may consider removing snapshot manually. Possible causes for snapshot removal failure: - Network connectivity issue, or vCenter server is too busy to serve the request - ESX host was unable to process snapshot removal request in a timely manner - Snapshot was already removed by another application "

The setup I have is 1 ESX host.
4 VMs amd one being the Veeam backup server. Only one backup job is receiving this error.
I am using virtual appliance option on my backup file.

Has anybody ever experienced this problem?

[Gostev]

Yes, if you search this forum for the above-mentioned error, you will see existing discussions about the same error. For virtual appliance mode, please make sure you are using the latest Veeam Backup version (4.1.2) as this has some enhancements around this.

To remove this snapshot with previous versions, try powering down Veeam server, and removing snapshot manually with vSphere Client.

[SamDLC]

Anton,

thanks for your help. Well I did what you suggested and that did the trick, something on the veeam server was preventing from removing the snapshots. Also it cleaned all snapshot disks from my datastore.
Thank you for your suggestion.

SAM

[Gostev]

Disks of the corresponding VM were still mounted to Veeam Backup server, which prevented snapshot removal. Disk may remain mounted, for example, if backup server resets in the midst of backup (which does not leave Veeam Backup a chance to dismount those disks). Veeam Backup 4.1.2 was made capable of handling such situations automatically by checking for any mounted disks upon startup, and unmounting those.