Version: 2.3.1 (using KDE 4.5.1)
When using external data source (like USB hard disk) there are quite common cases a disk is disconnected. Amarok doesn't have music source at this moment and stops playing.
When one closes Amarok, reconnects USB hard disk again and launches Amarok again, current playlist is gone (empty). As well as all cd booklet images are gone as well.
Steps to Reproduce:
Open music collections from external data source and add some to playlist. Then start playing. After a while disconnect external data source. Amarok stops playing.
Close Amarok and reconnect external data source. Start Amarok again and you should be able to see described problem.
I have observed this problem in various 2.x.x Amarok versions.
This was caused by the Dynamic collection bug 171213, solved in the upcoming Amarok 2.3.2
*** This bug has been marked as a duplicate of bug 171213 ***