That doesn't say hidden worksheet, it says hidden workbook, and tells you it's the PERSONAL.XLSB workbook.
I don't save my macros to or use a personal macro workbook so anything I suggest would be just a guess.
My buddy, Google, showed me these when searching for "
how to edit macro in personal.xlsb"
can't edit macro, says work book is hidden - Microsoft Community
Cannot Edit a Macro on a Hidden Workbook Error. How to Solve it?