I have an excel file that is corrupt. On 2/27/15 we were infected with a file corruption virus. I am not sure the name exactly, I just know it was detected very quickly, stopped and removed, and we thought we had recovered all of our damaged files from backup. However at this time I have 1 excel file that is saying it's corrupted when we try to open it similar to what it would say when hit by a virus. The thing that puzzles me is that the last modified date of the file says 2/12/15, before the virus hit. All of the other files that were hit had their modified dates changed to 2/27/15 as they were hit by the virus. So my question is how do I know if a virus caused this and could there possibly be a way to recover the file. I have tried all of the things I can find on the web, converting the file to .txt, using excel open and recover and have no success. I saw an old post from 2014 where someone sent the file to someone who could tell specifically if it was hit by a virus or not.
If anyone has any suggestions I would greatly appreciate it. We do perform nightly backups and I have 2 backup drives but all have the 2/12/15 file and are corrupted as well.
Thank you for your help!