VSS Snapshot issues on Server 2008R2

[Zamzi]

Hi guys

Wondering if someone can give me a hand with this.

Since upgrading to Hyper V 2012 R2 we have had an issue with one of our guest VM's which is 2008R2, with WSUS and File Server roles.

Unable to create snapshot (Microsoft Software Shadow Copy provider 1.0) (mode: Veeam application-aware processing). Details: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'.
The writer experienced a non-transient error. If the backup process is retried,
the error is likely to reoccur.
--tr:Failed to verify writers state.
--tr:Failed to perform pre-backup tasks.

Retrying snapshot creation attempt (Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'.
The writer experienced a non-transient error. If the backup process is retried,
the error is likely to reoccur.
--tr:Failed to verify writers state.
--tr:Failed to perform pre-backup tasks.)

However, its an intermittent issue and sometimes the backup completes perfectly, other times it will retry 2-5 times throw these errors and then decides to succeed.

Every time it fails it prompts us to format a disk that doesn't exist. See Imgur link: https://imgur.com/eP4J21n

Support case is #00820524

Thanks

Zamzi

[foggy]

Glyn, are there any related messages in the Windows Event Log? What about the 'vssadmin list writers' command output?