I have been hit with the VSS_WS_FAILED_AT_PREPARE_SNAPSHOT and non-transient error, and wondered what others have done to fix it.
22-06-2016 03:22:41 :: 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.)
According to other posts like microsoft-hyper-v-f25/hyper-v-vss-writer-vss-ws-failed-at-prepare-snapshot-t35736.html
, disabling application-aware backups will fix it, as its only needed for SQL, Exchange, Active Directory etc.
My guest VM is running MS Exchange 2013 fully updated, and thus I need the application-aware setting.
I checked avail disk space for all VHDs and there should be enough. I have not logged at case yet, as I would first check forums out and see if others have similiar issues and possible solutions.
HOST, Windows 2012 R2 fully updated running HYPER-V
GUEST, Windows 2012 R2 fully updated running Exchange 2013 and Active Directory.
All VSS services are running as expected, and other VM on the host seems to backup as expected (no errors in the history log).