Itl file problems on windows 10

I have used iTunes library for years with no problem. I have just recieved the following message. The file "iTunes Library.itl" does not appear to be a valid iTunes library file. iTunes has created a new iTunes library and renamed this file to "iTunes Library (Damaged) 1.itl". Now the library is empty. I added all my music back to itunes successfully but when I closed down and reloaded itunes i recieved the same message again and the library was empty again. Help!