LogFAQs > #930544330

Oh wow. Yeah I got nothing, that's messed up.

The only thing I can think, when I was dealing with a file that was doing weird things that I couldn't fix, was literally starting over. Fresh workbook, add in the old data (paste special values), formulas and formatting so it all looks the same. I think I had to do that a few times in Excel but it was mostly a Word problem.

I tried googling and there were some comments that it's a corrupt file issue...

Okay this is one thing that somebody said here: https://social.technet.microsoft.com/Forums/ie/en-US/bbda28fa-51b2-4d25-9256-29c10a64c7d5/excel-2007-changes-cell-formats-by-itself-at-random

Click on cell styles in the Home ribbon.
Right click on "Normal"
Click Modify
Click Format
Change format to General

This worked for me.

And more than a few posts saying that solved the issue for them.... but if "cell styles" is just what Format Cells was called back in that version then it's probably not a real solution? I forget all the past Excel iterations. My googling also turned up people saying that had the same problem even when starting from scratch but I like to think it wasn't fully from scratch and they copied-over whatever the old problem was to their new version...