Version:           2.0.1 (using KDE 4.1.3)
Installed from:    Ubuntu Packages

When I add an album to my music folder, amarok detected and add them to the collection without any problem. But several days later, 2 songs are gone from the collection and playlist. I checked my music folder, the songs are still there. I clicked 'Update Collection', but the songs still not appearing on the collection.