ITunes can't locate music files THAT I CAN

Question

Last night, when I opened iTunes, each song I clicked on gave me a "!" next to it, followed by this message:
"The song XYZ could not be used because the original file could not be found. Would you like to locate it?"
Well, I know exactly where the song is, which is where all the songs are and have been for some time on my LaCie external drive. They are, in fact, still there. When I go to a music file through the Finder and double-click the file name, it plays--through iTunes--and is recognized by iTunes thereafter. I could do this for all 2,500 songs, but I have a life to live in the next three to four years.
Why is this happening and, more importantly, what can be done about it?

Answer 1

this can also happen anytime the external drive is not available... i have 1/2 my library on an external drive and whenever the power goes out in my neighborhood, iTunes temporarilly looses the link to the external drive... my neighborhood was built in the 1920s, and the power goes out many times a year... i use an old powerbook for my iTunes computer, which i keep plugged into my stereo... when the power hiccups, the external drive goes down, but the powerbook continues on it's battery... if iTunes or the external drive get too confused by going up and down, then i just powercycle the external drive and reboot my powerbook and everything has normally gone back to normal... the power issues are part of the reason i wanted to keep as much as i could on the internal powerbook drive... and i keep everything backed up...
anyway, i'll try you suggestion for the "option" on launch... i had to replace my external drive which finally died (from 2001)... so now i need to relink the files back to iTunes, hopefully not manually since i have about 2500 files to fix... i did copy all the files from the internal disc to the new external drive and merged the libraries, then tried using the iTunes preferences to point to the folder in the external drive... but that didn't work in my case... it still sees 1/2 of the files still in the internal drive and still has "!" for all the files on the external drive...
for tlee61, this makes me wonder if you might not need to check the iTunes preferences to see where it is looking for your files. if you set it up to store all files on the external disc, and it is set up to copy in the files to the iTunes library, then that option in the preference file for the library location might have gotten changed inadvertently... if you have iTunes set up to NOT copy in the files, and your files are in random locations on the external drive, that may be much harder to solve... i'm not positive of the best approach... i think there may be an option for iTunes to search the drives for music, like when someone installs/runs iTunes for the 1st time... but i'm not sure, off the top of my head, how to trigger that... i may be looking for that option if i can't seem to figure out another way to relink my files... but i'm afraid that it will try to either copy everything from the external drive to the internal drive, where there is no more space, or that it will try to copy the files on the internal drive to the external drive, where i've already merged the files (and eliminated some duplications)...
i very much want to keep all the metadata... so i'm hesitent to experiment blindly too much since i don't want to do something that "imports" all the songs, but looses all the metadata... in my case, it would be easier to relink the files manually than attempt to recreate all the metadata...
if i find a solution besides just manually relinking files, i'll let you know...
i expect there is a way to solve this...
luck to us both-