A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
This worked for me. Good Luck: (Windows 10, Microsoft 365, Desktop (not browser version)).
When in Excel Desktop,
File -> Options -> Advanced
There's a section titled, "Editing Options".
**> Make sure the box right under that is CHECKED ("Enable fill handle and cell drag-and-drop").
The one under it was checked, as well.
When that box was NOT checked, I had the problem.
When I went in and checked that box, I did not.