Excel keeps changing some of my cell fonts to Courier New 10.

[JohnZ1156]

I have a workbook with about 10 Worksheets.
I usually set my font to Arial 12, then I save my workbook, but Excel keeps changing some of the cells, not all of them, back to Courier New 10.
I don't understand why?
I actually had to put code into a macro to go to the cells that keep changing and set them to the font and size that I want. And then run the macro.
This doesn’t make any sense to me.
Any ideas? It's just a little annoying.

 

[ISY]

Hi

You have an Office Windows stability problem