Hi everybody,
I have a very annoying problem.

On our server we have several folders with technical data sheets, they are all .xlsm files with macro and activeX buttons inside (made by me, excel 2013).
They are all very similar, and filesize is about ~230kb per file.
We are working on them since some years, and everything had gone fine until some days ago.
We have all win10 64 and excel 2013.

Here is what has been happening for a few days:

If I open a file on a pc other than mine: no problem, the file opens perfectly, and saves without any problem, mantaining its size.


If I open the same file on my pc by double clicking on file name: I can see Excel welcome screen "opening file bla bla bla.xlsm....", then everything disappear and excel closes.
Now if I open excel by double clicking on program icon... it opens my file in recovery mode, with activeX controls disabled.

If I open excel, and then open my file by open command, it opens fine.
But... if I now save it, its size is reduced to something about 75 kb.

Now, if I open the same file just saved on my pc (75kb) on another pc by double click... welcome sceen, opening bla bla bla... close.
And if I open excel by double clicking on program icon... it opens my file in recovery mode, with activeX controls disabled.
Instead if I open Excel and then the file (75kb) it opens fine.
And if I save it is still ~75kb.
Magic trick, now if I open the same file back on my pc from within excel or by double clicking....excel shows welcome screen and then closes!

Ok, re-reading it is quite a mess, but the meaning is that I have a problem which I cannot solve.
I tried a lot of different solutions, also a deep recover of Office, but nothing worked.

Any idea...?