Hi MooBooHome,
As per your description, “Incidentally, documents saved on the one drive will open.” it seems issue only occur when you open your Wod document form from Dropbox location. And also, your tried copying and pasting the documents to my desktop but issue still persist.
We’d give you the suggestions below and hope that will help you:
1.You can set up Mac in safe mode according to this article: Start up in safe mode.This can help you troubleshoot whether it is caused by third-party software.
2.Based on my experience for everyone else running into this problem, the solution is
Grant permission
How to fix permissions errors
https://appuals.com/office-2016-grant-access-error-on-macos/
***Disclaimer:****Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.*
If issue still persist even new created word document on your Mac OS, then I suspect components were corrupted somehow. You can go to the Applications folder In Finder and drag Microsoft Word.app to the trash. Then Restart your Mac Download this installer Install package and use it to reinstall Microsoft Word (the latest version 16.52). Then, restart your Mac and test.
Meanwhile, if you don’t mind could you please confirm whether other applications also get the same problem? Such as PowerPoint or Excel and etc.
I appreciate your understanding and stay safe!!
Best Regards
Waqas Muhammad