VSS MSMQ Writer fails for scheduled jobs only.

[wires]

I have a weird issue that is clearly something with permissions.

If I run the VM backup jobs or the agent backup job, I can backup my Exchange instance with no issues. As soon as I let a scheduled or chained job run (ie automatic), the VSS writer fails for MSMQ.

For the VM backup job, I see this inside the Exchange VM logs as a warning:

Event 8229 VSS
A VSS writer has rejected an event with error 0x00000000, The operation completed successfully.
. Changes that the writer made to the writer components while handling the event will not be available to the requester. Check the event log for related events from the application hosting the VSS writer.

Operation:
BackupComplete Event

Context:
Execution Context: Writer
Writer Class Id: {7e47b561-971a-46e6-96b9-696eeaa53b2a}
Writer Name: MSMQ Writer (MSMQ)
Writer Instance Name: MSMQ Writer (MSMQ)
Writer Instance ID: {d4660e8d-a75f-4832-8a58-815dfc6501c9}
Command Line: C:\Windows\system32\mqsvc.exe
Process ID: 2852

For the agent backup job on the host, I see this in the VM host logs as an error:

Event 10172, Hyper-V-VMMS
VSS writers inside virtual machine '<VMNAME>' failed to perform BackupComplete to its shadow copy (VSS snapshot) set: Catastrophic failure (0x8000FFFF). (Virtual machine ID 3C69C632-79FD-4278-949F-5589859CF8B0)

It's clearly a permissions issue from what the service uses vs me running as admin. Any help on which service needs to have permissions changed would be appreciated!

[Mildur]

If I run the VM backup jobs or the agent backup job, I can backup my Exchange instance with no issues. As soon as I let a scheduled or chained job run (ie automatic), the VSS writer fails for MSMQ.

If you run the backup job manually (from the vbr console), the same permission will be used.
If you have configured all necessary permissions from the guide, please open a sipport case with veeam (technical issues needs a support case).

Permissions for Exchange Guest processing:
https://helpcenter.veeam.com/docs/backu ... processing

To back up Microsoft Exchange data, the account must have the local Administrator permissions on the machine where Microsoft Exchange is installed.

[wires]

Thanks for the clarification. The user account for the guest meets those requirements. Manually running through VBR works, but any auto-run (like the host agent running after the VM manual trigger causes this error).

[wires]

Just posting back for others as this "healed" itself. I opened a ticket, but due to this being a community license, it expired before resolution.

What I believe "fixed" it was I added in a Windows 11 VM to do some sandbox testing which then exceeded and broke my 10 VM license. When I went back in, added it as an exclusion, then magically everything started to work fine again. Must have been some sort of permissions needed refreshing?

Anyways, all back running error/warning free again!