Conditional formatting bug

I am running Excel for Mac v16.16.27 (retired, I know). But for my occasional use only, it works just fine.....with one annoying bug. Whenever I try to set up some Conditional Formatting, it often times completes the generation of the formatting but then the ribbon bar becomes greyed out. So I do a File->Save, close Excel and re-open and everything is fine again and the formatting is in place. Any ideas what is causing this and how to stop it? Thx

there are a couple of things you can try to fix this issue-

• Make sure Excel for Mac is installed on your computer with the most recent version.
• Conflicts between Excel add-ins can occasionally result in unexpected behavior. Try disabling any installed add-ins to see if the problem still exists. Go to "Excel" > "Preferences" > "Add-ins" and uncheck any add-ins that are listed there to do this. Check to see if the problem is fixed by restarting Excel.
• You can attempt to repair the Office installation if the problem persists.

Best Regards.

• Make sure Excel for Mac is installed on your computer with the most recent version.
  Where do I find the latest version?
  
• Conflicts between Excel add-ins can occasionally result in unexpected behavior. Try disabling any installed add-ins to see if the problem still exists. Go to "Excel" > "Preferences" > "Add-ins" and uncheck any add-ins that are listed there to do this. Check to see if the problem is fixed by restarting Excel.
  There is no "Add-ins" in my Preferences area.
  
• You can attempt to repair the Office installation if the problem persists.
  How do I "repair" the installation?

1. https://support.microsoft.com/en-gb/...d-5e5f05a1a263

2. https://apple.stackexchange.com/ques...e-2016-for-mac

3. https://computertechnicians.com.au/h...rosoft-office/