On Mac devices, this error popups up because Endnote has missing Windows components. Endnote is part of Microsoft Office.
To resolve, please follow the instructions below:
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- Remove the SaveAsAdobePDF.ppam and SaveAsAdobePDF.xlam from the PowerPoint and Excel folders next to the Word folder.
- Launch Excel and PowerPoint and go to the menu Tools -> Excel Add-ins... and Tools -> PowerPoint Add-ins..., respectively, and remove the Save as Adobe PDF add-in, by unckecking it and removing it with the "-" button and then click OK.
- Restart Excel and PowerPoint and the problem should go away. If not, try several times to remove those options from the Tools menu until the problem goes away. I had to repeat this procedure in PowerPoint until this got fixed.