One of my Users has a pretty serious problem with files (doc, xls, pdf) that became corrupt out of the blue today. They display error messages like these: cannot be opened because there are problems with the content, or the file would open but content would be gibberish, or verify that the file is not corrupted and the extension matches the format, or the file you are trying to open <file name.xls .doc .pdf>, is in different format than specified by the file extension, verify that the file is not corrupted and is from a trusted source before opening then "I get do yo want to open file now?" question and when opens its gibberish. The same happens on different PCs, different locations but all of the files are the same they were in different locations because of the migration. At the same time some of the files like Access, or JPEG created earlier than 9/20 open easily.
Make sure you open the file with the right program: doc>Word xls>Excel pdf>Adobe reader(or other software)
Since these files cannot be opened in different machines, we recommend create a blank new file to see if it can be opened normally.
If it works fine, you might need to do a scan with antivirus tool for your computer to see if virus got the files corrupted.
If it cannot be opened, repairing your Office suites in Control panel>Program and features>Office>Change>Repair can help you fix your problem.
TechNet Community Support
I had two instances and I dealt with both differently: 1st I successfully booted in Repair Mode, ran System Restore to a week before the event, after reboot I ran Disk Cleanup deleting files from Temp, Temp Internet and Recycle Bin, installed Malwarebytes, and running full scan and 2nd I created a KickStart USB Drive from HitmanPro, booted from it, scanning the entire laptop and deleting everything detected by the software. With 2nd device the files were recovered and 1st device I had to find old files and replace the effected ones.
Hope this helps you guys.
Just to add: I found that the best way to combat any infections is by taking away Administrative access from the Users and I have never had any luck with McAfee, Norton, etc but combination of AVG Free, or Avast Free, or Panda Free, and Malwarebytes Free worked for me.
How did the files (doc, xls, pdf) become corrupted? Was there any hard disk failure or any other problem occurred in your system? Are you sure the files are corrupted or is there any problem with the programs used to open them? I would suggest you to check these files on Hex editor and verify the corruption first. If files are really corrupted, then try some third-party recovery software to recover your data from those corrupted files.
I can recommend you SysInfoTools products here to recover data from your corrupt files.
Try SysInfoTools MS Word Recovery to fix corrupt Word documents, SysInfoTools MS Excel Recovery to fix corrupt Excel spreadsheets and SysInfoTools PDF Recovery to fix corrupt PDF files. Try demo versions of these software first. To read more about them, visit: sysinfotools.