Recover PDF files/documents

Hello,

I realized 'some' of my adobe files in my hard disk cannot be opened with 'File corrupt' error. I know these files are valid and usable (at least before the issue)

The interesting thing is this issue is seen in some adobe files and not in others.
For some files I have backups but for some I don't. So need to find a way to recover them.

Please help!

Using search machine to finding out a great answer can be too long. Visit following source- https://social.technet.microsoft.com...eitproprevious - where it is easy to find proper category and to find out unusual decision for corrupted .pdf files.