Music corrupted, illegible

Hi,

I've just noticed that some of my tracks are corrupted. When I want to read a music within iTunes, the music doesn't launch and nothing happens, and when I check in the iTunes library folder, the tracks I can't read don't have their cover anymore, and I can't even read it on another software like VLC for example.

I've spent years to have an organized library, and now, I've discovered that I can't read all of my music anymore. Approximatively half of my music doesn't work. Some of my tracks are corrupted and I don't know what to do to recover the originals.

I hope someone has the solution because it's outrageous to have this result after spending so many times on it. Furthermore, the tracks corrupted seem to be the one I've listened the most ... Great !

Thks for your support