Correct password will not work to right-click unprotect sheet, but DOES work in VBA

[9tanstaafl9]

Right clicking and choosing to unprotect a sheet, and entering the correct password (correct capitalization too) DOES NOT WORK. My macro that I have used for years to unlock this workbook DOES WORK. Using the same password. I have been using this workbook for 10 years and have never had this problem before.

I'm sure this is something supremely stupid, but in all my years of working with Excel it hasn't happened before. I'm wondering if I could have done something accidentally that changed how passwords work for this workbook?

And in case you're wondering why it matters if I have a macro that will unlock it, it's because that macro is on my personal.xls and I don't want he people I'm giving it to to have it. Slowing them down a bit helps keep me same.

Thanks in advance, and again I apologize if this was covered elsewhere, I couldn't find it. Search terms are too general.