Are you willing to lose all your customized changes to any of the toolbars?
If yes...
Close Excel
Use windows search and look for *.xlb (location and name will vary with the
versions of windows and excel you used) Remember to look through hidden folders
for hidden files.
Rename those *.xlb file to *.xlbOLD
restart excel and test it.
If it doesn't help, close excel and delete any newly created *.xlb files and
rename the *.xlbOLD back to *.xlb.
