recently I upgraded from ubuntu 8.10 to 9.04. this made me upgrade my amarok from 1.4 to 2.1.1. At first everything worked fine, but when I rescanned my collection everything became messed up - e.g. some "Make Some Noise' album by Liquid Soul was tagged as Led Zeppelin CD "Duke Ellington and John Coltrane". Fortunately, only small part of my music was affected by this bug as I moved into new hard drive too.

How can I prevent from being affected by this in future?

Don't worry, your tags have not been rewritten, you probably just a have a corrupted database.

Actually, when upgrading to 9.04 this gives you Amarok 2.0.2, you get Amarok 2.1.1 only if you have the jaunty-backports repository enabled.

If you had a SQLite databse in 1.4 (which was the default) there is an import wizard that should help you importing your database to the now default MySQL embedded. Also, there was a db version change from 2.0 to 2.1, so if you have a tag mismatch, you better erase the database in ~/.kde/share/apps/amarok/mysqle/ and scan your collection again, this should solve the problem for now.

The db import from 1.4 SQLite to the next version, 2.2 should go flawlessly. So far, you can't directly import databases from other formats.

well, it turned out to be a database issue, I erased it and rescanned collection and everything seems ok right now.

big thanks for quick support! (: