Strange file corruption behaviour

Hi all 

We have from recent times some strange behaviour in file corruption , substantially the file ( resident on a fileserver ) dont give any hint\ error about corruption but directly losses many parts , in particular all the content of the sheets ( not the models ) like cells \ elements ( all resident on sheets ) and not eventual references.

On opening the file dont give any error messages , first time we was aiming for a "user" issue but now we had 3 same experience with different users and different files ( the files has been modified only from the specif user )

Any suggestion ???