Have you encountered this error dialog:
In this case, I was moving a project folder. I had just finished editing a presentation, closed the file and PowerPoint. But I was unable to move the entire folder. Frustration!
Often, PowerPoint is still open as a background application even though it has been closed. Why – I do not know, but it definitely causes lots of user frustration.
1. Right-click on the bottom task bar and select TASK MANAGER
2. Scroll down, past the active Apps into the BACKGROUND PROCESSES and look for MICROSOFT POWERPOINT (it will be the same name with all versions of PPT).
3. Select it and click END TASK.
4. Now click TRY AGAIN on the error dialog and all should do as you wanted (move, delete, rename, etc.).
– Troy @ TLC