A VSS critical writer has failed: SqlServerWriter

[Dima P.]

Hello Tom,

Thanks for the input. VSS processing is handled by local system account (basically that's the account used by Veeam Agent for Windows), so the solution looks correct. Cheers!

[FireExit]

Almost 9 years later, I have four "identical" customer remote desktop servers, with ACT7 and StorageCraft, three have MSSQL$ACT7 running as local system and fail, one has MSSQL$SQLEXPRESS running as NT Service\MSSQL$SQLEXPRESS and works. [VBR application aware backup / Hyper-V checkpoints].

I changed the SQL service to local service, restarted the SQL Service and the VSS Writer service, and they work. Thanks Bellsys2765 !

[Mike.Powell]

https://www.veeam.com/kb2798 This has been a specifically documented situation for about 7 years.
I haven't seen this one in AGES but the ACT software is key "

Backup job fails with a SQL VSS Writer error after installing ACT! Software