PowerPoint for Mac - how to remove "upload pending" items from "recent" list?

Maxi_93 and for others with the same issue: you can reset PowerPoint back to its default settings by wiping its data directory -- please note the instructions below may reset some preferences and will delete pending documents that have yet to be uploaded to O365.

1. Quit PowerPoint if it is open.

2. Click on Finder in the dock to open a file browser

3. Press Cmd+Shift+G to open the Go To window. Paste this into the text field: ~/Library/Containers/com.microsoft.Powerpoint

4. You should see one folder "Data". Trash it.

5. Open PowerPoint.

PowerPoint should show the first-time welcome screen and your recent documents will no longer be pending upload. If you wish to undo this change, move the Data folder from the trash back into the ~/Library/Containers/com.microsoft.Powerpoint folder from step 3.