You can try the following beforehand
Install the latest update
Repair Office programs
Start Office applications in safe mode
Identify possible problems with the add-in
Hope I was able to help you with this info.
If this not helps…
Please add more information.
Which operating system?
Which Office version?
Where are the files stored?
(OneDrive, Sharepoint, hard drive, USB, etc.).
Attach some photos with the problem and explain your concern/problem step by step on the basis of these photos.
Even better, insert one of these files (without sensitive data).
So no one needs to guess and exclude many ways/causes with a lot of communicative time.
Thank you for your understanding and patience
I know I don't know anything (Socrates)