One of the bugs I encountered after upgrading to Fedora 17 is that my music library seemed to have disappeared in Rhythmbox. In fact, everything appeared in the Missing Files view. The strange thing is that all the files appeared exactly where Rhythmbox thought they should be. In fact, I could even play them directly from the Missing Files view!
Anyway, after a bit of searching, it appears that I am facing this bug. You see, on my laptop, I encrypt the /home directory. Back on Fedora 16, some bug in gvfs or udisks caused things to think that that directory was a removable partition. Something must have been fixed in Fedora 17, because it's no longer marked that way (which is good, because I hate seeing it in nautilus.) However, Rhythmbox still thinks those files should be on a separate partition and doesn't correctly update itself (the aforementioned bug.)
This is pretty easy to fix, in fact. Since /home is now no longer considered a separate mount point, you just have to remove those indicators from Rhythmbox's config. The config is an XML file that's been pretty-printed, so the offending information appears on a single line (per file entry). That makes fixing it a pretty simple thing to do:
$ cd ~/.local/share/rhythmbox/
$ cp rhythmdb.xml rhythmdb.xml.backup
$ sed -i -e '/<mountpoint>/d' rhythmdb.xml