I just got a "Safety Freeze" error [1] - essentially some inconsistency with my backup. Backblaze will not tell me the actual cause of this inconsistency. It's possible that some data might be missing - Backblaze doesn't tell me though.
The only official solution is to manually check all files (millions in my case). I also can't download a full backup since Backblaze only allows downloads of up to 500GB at once. So my only option is to do a full hard drive restore, costing $189 + customs in Europe, so at the end probably closer to 300€. But even then I won't know if/which of my data was corrupted.
What bugs me is that the Backblaze desktop software should be able to resolve this - it should be possible to do a hash of all the files that are in the most recent backup, and cross-check it with the hashes of the files on my machine.
Not sure what I should do now.
Edit: This is the response from the Backblaze support:
> I apologize, but this [=manually checking all files] would in fact be the only sure fire way if you are concerned about any deleted files. There wouldn't be a way to compare hashes the way you describe in this case as that mechanism is simply not implemented into the Backblaze software. The Backblaze software is intended to prevent data loss. It would not be intended to be able to automatically cross reference local and server data against each other to display what is and is not backed up on our servers.
They can't be serious with this?