CommVault: Dealing with VSS Snapshot failures

CommVault backups might fail from time to time due to a bad VSS functioning. There is plenty of Microsoft articles on how to deal with VSS Snapshot failures. In this article we will focus on a particular error that occurs while a VSS snapshot fails to be taken.

Job error description

Error Code: [19:857]
Description: The job has failed because the VSS snapshot could not be created
Source: spcvma54, Process: clBackup

Troubleshooting

First of all I will make sure that the following is ticked off:

1. No errors are seen in the VSS Providers list

   vssadmin list providers

2. No errors are found in the VSS Writers list

   vssadmin list writers

3. There’s enough free space to create a Shadow Copy
   You can test by creating a shadow copy manually. Eventually set the Maximum size to “No Limit”.
4. Check Event Viewer > Windows Logs > Application.

In my case, it was the Event Viewer that shed a light to the issue resolution. Among other VSS events, there was this little “innocent” error indicating a problem with one of the Shadow Copy Providers, eventhough this was not listed in the command line.

Volume Shadow Copy Service error: Error creating the Shadow Copy Provider COM class with CLSID {3e02620c-e180-44f3-b154-2473646e4cb8} [0x80040154, Class not registered
].

Operation:
Obtain a callable interface for this provider
Add a Volume to a Shadow Copy Set

Context:
Provider ID: {74600e39-7dc5-4567-a03b-f091d6c7b092}
Class ID: {3e02620c-e180-44f3-b154-2473646e4cb8}
Snapshot Context: 25
Execution Context: Coordinator

Solution

From the error logs above we see that there’s an issue with the Shadow Copy Provider with CLSID: 3e02620c-e180-44f3-b154-2473646e4cb8

1. Open Registry Editor and navigate to: http://hkey_local_machine/SYSTEM/CurrentControlSet/services/VSS/Providers/
2. It is always recommended to back up the registry keys, do so for your safety 😉
3. Find the registry key which corresponds with the CLSID seen from the Event Viewer. In my case it was Hyper-V IC Software Shadow Copy.
4. Delete this key (or any other that reflects with erros in the Event Logs)
5. Reboot the server and backups should work again.

You can check the creation of a shadow copy by using the following command:

C:\windows\system32>vssadmin list shadows

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001-2013 Microsoft Corp.

Contents of shadow copy set ID: {9d7b650a-377f-4e49-8e92-06d025abcf8b}
   Contained 1 shadow copies at creation time: 23/12/2020 10:39:21
      Shadow Copy ID: {d6995554-1430-4eb8-b7fa-e454cabaeeb5}
         Original Volume: (E:)\\?\Volume{1fe0ecbf-65fc-45cb-9f3e-891a63280da6}\
         Shadow Copy Volume: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1

         Originating Machine: STORSERV01.STORCOM.COM
         Service Machine: STORSERV01.STORCOM.COM
         Provider: 'Microsoft Software Shadow Copy provider 1.0'
         Type: DataVolumeRollback
         Attributes: Persistent, No auto release, No writers, Differential

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