I tried to use this backup solution but ended up running into obscure errors that halted the entire backup process: “Abort due to constraint violation UNIQUE constraint failed: FilesetEntry.FilesetID, FilesetEntry.FileID”

There is an open issue from 2019 about this error. Even if it was fixed, though, the more alarming thing is that the system cannot gracefully recover. I used the free version of their monitoring service – which they sell as a solution to monitor the status of backups – and it did not report any errors from this. So not only does the solution not work, the monitoring service doesn't either.

The backup I was trying to perform had approximately 22TB of data across 6.5 million files. It is not practical to fix individual file compatibility issues to complete the backup successfully.