Nine Things That Often Go Wrong in PowerPoint 2013
You've run out of hard disk space.
Open the File Explorer window (type File Explorer and click or tap the File Explorer button) and rummage through your hard drive, looking for files you don’t need. Delete enough files to free up a few megabytes and then press Alt+Tab to move back to PowerPoint and save your file.
If your hard drive is full and you can’t find more than a few files to delete, try double-clicking the Recycle Bin icon and choosing File→Empty Recycle Bin. This often frees up additional hard drive space.
If that doesn’t work, type Disk Cleanup and click or tap the Disk Cleanup button. The Disk Cleanup program scans your hard drive for unnecessary files and offers to remove them for you. It can often free up many megabytes of hard drive space.