Hey Geoff,
Unfortunately, Time Machine is not supported for backing up Roon.
Because Roon’s database is constantly updated in the background, programs like Time Machine tend to save random pieces of Roon’s database, instead of saving a full snapshot of the database at a given point in time. This generally means that when you restore, you get a mix of different files from different times, resulting in corruption.
Sorry for the trouble here @petridish. Have you done any manual backups you can fall back on?