Forum Discussion
Excel Corruption when moved to personal vault
I created a personal vault in One Drive, and moved some excel files to there and now all of them indicate "cannot open the file Budget.xlsx because the file format or file extension is not valid. th...
I don't know if this will help, but I have had some similar experiences lately after migrating all of my files from one Mac to another. Those Office 365 files in OneDrive got messed up somehow; I could still see them listed in the Finder (if you don't have a Mac, Finder is the package that just makes it possible to navigate through the storage system, opening folders, seeing files listed)...so I could see the files clearly listed, but if I tried to open them I got error messages such as you're seeing.
However, if I drag and drop such a file to the desktop, I could then open it, and save it back to the folder where I wanted it. From there on out, it worked normally.
That may not be your issue, but I wanted to offer it as a possibility.