This has always been a problem for me. When I add a folder of music to iTunes that contains a .m3u file, about 75% of the time my application gets the beach ball indefinitely until I force quit iTunes. I thought that it might have been an issue of a slow hard drive, but I recently upgraded to a SDD which has not improved this issue. Running a search, it seems like this is not an issue for anyone else, but if anyone has any insight to this problem it would be greatly appreciated! Edit: I am running Mountain Lion, but this was a problem on Lion as well.