There's no way to fix the corrupt data file. Hopefully you are backing up your documents folder, in which case you will need to restore the file from your backup routine from before the file was damaged. If you have OneDrive syncing your documents folder it may have a previous version of the file you can use.
The only time I have ever seen this happen is on hardware that is starting to fail -- I would recommend running a system disk check to see if you have any problems with your storage.