Restoring a full backup of a Read-Only database: fine.
Then restoring a diff backup of that same database: won’t work.
I’ve just wasted best part of a day chasing that one down. What’s worse is I should have remembered, as I’ve seen this before fairly recently (well, in the last year or so)…
I’ve not been well, y’know.
To add to the fun, this was using some third-party backup software, rather than SQL Server’s native backups. There was a sort of error message, but it was of the form “I’m sorry, Dave, I can’t do that”:
Cannot apply the backup on device LiteSpeed for SQL Server backup file to database '<foo>'.
Yeah. Helpful. In LiteSpeed’s defence, it’s a message generated by SQL Server.