DPM server 2016 5.0.622.0

Question

When schedule backup job start, after few minutes son of the hyper-V VMs backup failed. I get the error code 8229 on hyper-V host and event ID 8194 on VM. Job is getting failed.

On Hyper-V host

A VSS writer has rejected an event with error 0x800423f4, The writer experienced a non-transient error.  If the backup process is retried,
the error is likely to reoccur.
. 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:
   PrepareForSnapshot Event

Context:
   Execution Context: Writer
   Writer Class Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
   Writer Name: Microsoft Hyper-V VSS Writer
   Writer Instance ID: {269510e2-658b-4085-8915-7c6e45b796e8}
   Command Line: C:\Windows\system32\vmms.exe

On VMs for which Backup failed.


Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface.  hr = 0x80070005, Access is denied.
. This is often caused by incorrect security settings in either the writer or requestor process. 

Operation:
   PrepareForSnapshot Event

Context:
   Execution Context: Writer
   Writer Class Id: {0ff1ce16-0201-0000-0000-000000000000}
   Writer Name: OSearch16 VSS Writer
   Writer Instance Name: OSearch Replication Service
   Writer Instance ID: {b5ac8416-b9b1-482b-90ab-d3a10a447981}

Answer 1

Hi,

According to the error, it seems that the Windows Server Backup is not working.

Error code 8194 is an "Accessed Denied" error caused by the inability of one or more VSS system writers to communicate with the Remote Backup VSS requestor process via the "COM" calls exposed in the IVssWriterCallback interface. Try to add service account permission to COM.

http://help.remote-backup.com/index.php?/Knowledgebase/Article/View/327/0/eliminating-vss-error-8194-from-event-log

Locate the writer on the list, and restart the correlating service, then rerun vssadmin list writers to ensure the writer is stable.