Backup file version mismatch: scale-out backup repository rescan is required.

When reverting the snapshot, did you undo the V12 upgrade? And during the rescan, are there any offload tasks actively running?

What build of v12 are you on? Latest patch? You haven’t mentioned doing a rescan of your entire SOBR just the azure tier so I would start there. This might involve some log do ing or even making a new full backup depending on the issue. So if you’ve got a support contract with Veeam I’d definitely engage them ASAP

As noted if you used one version of Veeam and then the snapshot reverts it to a previous version you can have this issue. Make sure Veeam is patched to the same version prior to the snapshot revert.

Yes it had reverted back to 11 so I am assuming an SOBR happened during the window of which got it out of whack. but I had paused all jobs, set the window to 2 hours in the past and then waited 10 minutes before rescan, it finds/syncs things but then fails to SOBR offload after re-enabling the jobs and the all time window, making sure no jobs are running prior to forcing it. I think since we need to enable immutability anyway I will just start fresh with a new storage account at this point. Thanks for the feedback. 

Well that’s really an issue as V12 changed in many ways and therefore you’ll have incompatibilities in your blob storage account when accessing it with V11. If you can start with a new storage account, then that’s probably the best path. Just upgrade to V12 before that, so that you benefit from all the object storage improvements. If you want immutability with blob storage, then you’ll need to upgrade first anyway.

Besides that, only our support will be able to analyze your blob storage and decide a way to get it back working. So if you want to continue using it, I would suggest to open a case, just as @MicoolPaul said.