Dear respected Denise Brumm,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
I’m sorry you’re having a problem but based on your description we can work together to resolve it.
For the situation you encountered, we deeply understand the inconvenience caused and apologize for it.
As per your description, may I ask did you get any error message when you trying to open file from stored location? If possible, could you please upload screenshot for our reference, so we can understand your exact scenario and provide our suggestion in a productive manner, perhaps some related screenshots will be helpful.
If you stored your files into OneDrive location, are you able to open in Office 365 application on your new Mac OS? It will be helpful to find the reason.
We appreciate your understanding that sometimes the initial suggestions may not resolve the problem very soon. However, we can work together to narrow down and resolve the situation. So, please kindly provide more information below to let us work further.
- Confirm the version of Mac OS and Office
Find out which macOS your Mac is using
About Office: What version of Office am I using?
2.Can you recall when this behavior starts e.g., after Office update or Mac OS.
Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Waqas Muhammad