A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Dear Steve
It seems that you previous encounter some Adobe add-ins issues when you use PowerPoint for Mac and the add-in is removed like what is mentioned in New Error: "Run-time error '53'" ... MacPDFM - Microsoft Community.
If yes, could you check whether there are some updates come from Adobe? If yes, could you upload the Adobe application like what is mentioned by Jim Gordon in the thread PowerPoint couldn't load the add-in - Microsoft Community, restart the Mac and do a test to see the result?
Does the issue occur suddenly? If yes, what did you do before the issue happened? Could you provide the reproducing steps of the issue for our reference?
Meanwhile, I'd like you to provide the version number of the PowerPoint for Mac application and the Mac operating system you are using for our confirmation.
Thank you for your effort and time.
Sincerely
Cliff | Microsoft Community Moderator