Version: 2.1 (using KDE 4.2.4) OS: Linux Installed from: Ubuntu Packages When I upgraded Amarok 2.0.x to 2.1, it would only display three songs in my collection. Updating the collection didn't do anything. Only when I went to the collection settings and did a full rescan, it found the rest of the songs. I'm using Amarok from http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu on Ubuntu Jaunty.
I should add: the first time I ran Amarok after the upgrade, it crashed (but with no usable backtrace). The second time, it worked, but lost the collection.
I believe this is fixed in current trunk (eventual Amarok 2.2).