So you can get the number formatted correctly with regard to the number of decimals that you choose, but the comma separator is not showing.
Is this happening in all workbooks, old and new, or just in a specific one
Ok in that case the problem is probably in your system regional settings (Mac preferences). Make sure the correct country is chosen and that comma is set to be your number separator
Hope this helps
Ok just to make sure it is not an excel setting, check your International Settings in Excel Preferences and make sure the 'Use system separators" box is checked
It should be under Edit > Preferences
I can give you the code that will set it up for you if you like