Running windows 2008 sp2 server. When a backup is performed get this event id 8194. Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0x80070005. This is often caused by incorrect security settings in either the writer or requestor process. Operation:Gathering Writer DataContext:Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}Writer Name: System WriterWriter Instance ID: {a20ffb2e-e9b6-446a-8e8c-76adfcbc6acb}Performed vssadmin list writers and the system writer is stable, but the last error is non-retryable error. Been working on this for a couple of days - have stop and started cryptic services and the writer is fine. Rebooting the writer becomes fine. Contacted my backup vendor ARCServe, because this is when the error occurs, but since this is the system writer it's a microsoft issue. ARCServe claims there are fixes for this. Is there? If so, how do i get them?Thanks

Hi Franky34,I have seen the similar thread way back in june 2009, and it was said that product group was aware of the above problem and they are looking at the issue. Please find the supporting link below http://social.technet.microsoft.com/Forums/en/windowsbackup/thread/7ab3aec6-0cf9-44a8-8f2f-c37d43114a0fAnd there is a technet article to identify the root cause of the event id 8194, hope these might helphttp://technet.microsoft.com/en-us/library/cc734235(WS.10).aspx

Hi Franky,The error translates to an access denied. This issue occurs when using a 3rd party backup program that utilizes Windows VSS and has it's own requestor.Cause:===========In the above case: It looks like the requestor (the backup application) does not allow system writer to call back into their process. Most likely you call Technical details: The event message above is coming from system writer. At this moment, this is a writer that is running under an administrative account which is not Local System. But COM disables access by default to everybody except "SELF" (the current logon session) and Local SYSTEM. This is why you are getting the callback error event, and the failed system writer state.Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}Writer Name: System WriterWriter Instance ID: {a20ffb2e-e9b6-446a-8e8c-76adfcbc6acb} Resolution: ============In addition to Sainath's suggestion, you may see the article below:http://msdn.microsoft.com/en-us/library/aa384604(VS.85).aspxTo resolve this error, a secure registry location needs to be modified to instruct VSS that a given user is safe to run a VSS writer.The following example grants access to the "MyDomain\MyUser" account:HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesVSSVssAccessControl <--- ADD KEYMyDomain\MyUser = 1 <--- ADD VALUEHope it helps,Sincerely,Wilson Jia This posting is provided "AS IS" with no warranties, and confers no rights.

Hi Franky,Did you had a chance to go thrugh the posts and implemented the same ?

Have tried and all writers were getting errors. Have set back to original state and looking for more info before i try to change again.Guess i'm confused. The registry matches another server which works just fine. Do i add another user - which caused the other writers to produce errors or do i change nt authority\network to something else?

This may or may not be relevant to you as I was seeing (and just solved) the same error on my Windows Vista client machine. Originally I couldn't figure out what "the requestor (the backup application) does not allow system writer to call back into their process" meant as the only backup happening on my PC that could be related to the Volume Shadow Copy Service was System Restore. Other users reported Mozy backup service as a source of their problem but I had no backup software or process on my machine. I finally made the connection that Revo Unistaller creates a restore point each time it does an unistall. I was able to reproduce this by running Revo Uninstaller with the Event Viewer open and when I refreshed the Event Viewer, the Event ID 8194 Volume Shadow Copy Service error occurred. I now know what's causing the error and figure I can now find a way to make it stop. However, knowing that I have control over the error (I don't have to run Revo Uninstaller) makes me worry a lot less about it. Hope this helps.