When closing a pdf Adobe reader proposes to save even if no edit is made

[jmmatrat]

I open a pdf file with Adobe reader just to read the content, when I close it, Adobe always display a box to save it.

I have removed and installed it again and the issue is still there.

Any idea?

[Test Screen Name]

Some PDFs do this, for several reasons. Not a fault in Reader. 

[JR Boulay]

When it opens a damaged or corrupted PDF Acrobat (Reader, Pro and Standard) makes silent repairs.

So you're prompted to save.

[Bernd Alheit]

Or Javascript code modifies the document.