itunes and the external harddrive problem

I have a TB external hard-drive and keep all my music that I play through itunes on it. Yesterday, a song was played through itunes without the drive attached and of course not finding it skips all of them leaving a little exclamation mark. When I re-attached the drive, of course the music plays, but I cant put it on shuffle without it skipping all the files marked with an exclamation mark. Is there a way of removing the exclamation mark without clicking on every single one, or is my only option to remove all of them and re-import.

 

Sometimes the best answer is just brute force: with the hd once again connected create a play list with the select all option, this should force itunes to search and find everything, which should get rid of your exclamation marks. Oh yeah, don't forget to hold ctrl and check any box to select/deselect the whole column of tracks for inclusion.