A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I'm having the exact same problem. It worked fine for a day or two, but now only opens files from within Excel. I thought my files were corrupt at first and went to look at backups, but when the backups also opened up "blank", I realized there was more to it.
I've found numerous threads outside this one with the same problem and have tried a few of the fixes with no success.
Could this be a upgrade issue?