Version:           2.4.3 (using KDE 4.7.3) 
OS:                Linux

The first thing I noticed is that after starting my machine, my collection was empty. Doing a full-scan repopulated it, but it happened again many times after the login in the next days. It also happened one day in the middle of a session.

Then, I switched to my local MySQL (easier to track issues, no need to stop amarok and mount its db on a mysql). A couple of times, the collection was rebuilt automatically  at start-up (takes some time).
I also noticed that after some partial updates (automatic or not), my collection would only contain a few tracks. A full scan would repopulate it.
At that moment, I realized that I lost a big part of my stats, including the ratings that took my quite some time to do. In the DB, I saw that there were new entries for the tracks in the table 'urls', so the entries in the table statistics were pointing on urls that were not existing any more (they also had the flag 'deleted').

For the moment, the only solutions I have are:
- restore the dump of the previous day
- manually apply the ratings I saved (using a joint between urls and statistics)

Reproducible: Sometimes

Steps to Reproduce:
Start amarok, play and rate tracks 

Actual Results:  
Collection get empty or only have a few tracks
Stats are lost

Expected Results:  
Stats should not be lost