Over a month ago, we installed veeam and started testing it with some of our VMs - all was and is still going pretty well EXCEPT for one server - it happens to be our DC and Exchange server (1 VM).
This server was setup with a job and VSS was enabled for this server - being exchange and AD. It was setup as a base job with normal incrementals.
The very first full backup of this job ran perfect - then i tried to run the job again shortly after the success of the base just to check the increments would run and BANG - i got this error from veeam (although the error would suggest that it came from VSS on the guest)...VSS_E_SNAPSHOT_SET_IN_PROGRESS.
Every increment failed with that error.
I tried rebooting the server, didnt help, checked the vssadmin writers and providers (all good and no conflicting writers/providers), tried applying MS VSS fix to resolve 'numerous VSS issues', didnt help - i also tried deleting this backup set from disc and trying a full new backup, same error even off the base this time - tried deleting the job and creating a whole new job, same error - tried installing veeam on a completely different server and running the job from there, same error.
I wasnt getting anywhere with this so i got onto veeam support - that was about 3 weeks ago now. the Veeam support guys have been on our network several times and this job has even been escalated but they absolutely have no idea what is going on here or what the cause is....or more importantly how to fix it.
It seems like another week is about to pass with no progress so i am posting this issue here to see if anyone in the community has seen something like this or has any ideas.
pls dont just say "its a VSS issue", thats no help - i know the error makes it ridiculously obvious that its a vss issue but i dont see how a vss snapshot that is in progress can survive a reboot etc and the Symantec product that used to image this server with VSS did so for years without an error anything like this - this server and its VSS is a solid constant - Veeam is the new variable to this problem. Sometimes programs issues out "errors" like VSS_E_SNAPSHOT_SET_IN_PROGRESS that point to an obvious cause but in fact the error message does not correlate at all to the actual reason why that message was handed out - so i think that might be happening here, a "vss looking message" is being handed out but i think the problem is somewhere else in the process and i am not seeing any kind of error message for that.
The veeam guys are also not able to find the Veeam folder in the app data location of this guest to go through the veeamvsssupport logs - the folder is just never created like it is on other vm's. There are no events in the guest log at the time of a backup to suggest something is wrong or right. There are just not many clues.
Veeam support and the escalation team are struggling with this one so i am hoping wealth of knowledge in the community can help

Thanks guys