Filed downstream as https://bugzilla.redhat.com/show_bug.cgi?id=1013858 , thought it would be worth reporting upstream too.

Rhythmbox (rhythmbox-3.0-3.fc20.x86_64) seems to crash relatively often after importing tracks, with this traceback:

Truncated backtrace:
Thread no. 1 (6 frames)
 #0 rb_list_model_find at rb-list-model.c:179
 #1 rb_list_model_remove_item at rb-list-model.c:277
 #2 task_expired at rb-task-list.c:138
 #7 g_main_context_iteration at gmain.c:3773
 #8 g_application_run at gapplication.c:1635
 #9 rb_application_run at rb-application.c:646

(full trace will be attached). I hit it multiple times over the last two days while transferring tracks to an SD card and cleaning my library as I went; I'd find some wrongly-located files, say, remove them from the RB database, move the files, use the 'add songs' page to add them back into the RB database, and it'd crash on completion.