iTunes deleting music files

[wingsabr]

iTunes is doing some weird things lately. I have a MPB 2011 and I have the latest iTunes. This morning I noticed that about 15gb's of my music was gone. I figured I deleted it by accident, so I just added it back from my external. This evening I went to listen to some music and found that some of the tracks had the ! next to them. I checked the file size in the finder and it was the same size, but when I added my files again there was no difference.

I had to delete all of the files from iTunes and readd them in the library. Someone please help me. I can't keep doing this every time I want to listen to music.

[Consultant]

It's NOT gone.

Connect external disk first before opening iTunes.

Quit iTunes before ejecting external disk.

[TARDIS61]

It's NOT gone.

Connect external disk first before opening iTunes.

Quit iTunes before ejecting external disk.I am experiencing the same problem as listed above (recieving the ! -message). Is the best thing to do is to delete all of the follows and then follow your tip ?

[wingsabr]

It's NOT gone.

Connect external disk first before opening iTunes.

Quit iTunes before ejecting external disk.

thank you for the help, but my itunes is stored on the same hdd as my system. I don't have a separate drive that I use to access.