"Recover an earlier version of an Office file
If the AutoRecover option is turned on, you can automatically save versions of your file while you’re working on it. How you recover something depends on when you saved it. . . ."
"If you haven’t saved the fileGood short article to get you out of a tough situation in Word, Excel or PowerPoint 2010 or 2013.
- Click File > Info > Manage Versions > Recover Unsaved Documents in Word, Recover Unsaved Workbooks in Excel, or Recover Unsaved Presentations in PowerPoint. . . ."