I keep my 20k+ songs on an external drive because the of tiny drive in my MacBook Air. Unfortunately after i removed the drive, all my tracks in iTunes show the exclamation mark. Is there any way to tell iTunes "Hey, now all the tracks are here again"? Get info or play works for individual tracks, but for 20k+ tracks it's a hassle. I haven't tried iTunes track CPR because it needs a very ordered library folder (mine does not strictly follow the Artist/Album/Track file hierarchy) and I'm afraid it might damage something.
I would gladly use another music app, but iTunes is the only way to sync songs to my iPhone.