I have been using an excel file for a few weeks with no issues, all of a
sudden I am getting an error message: The value you entered is not valid. A
user has restricted values that can be put into this cell. Retry. Cancel.

I started this workbook, I have done a fair amount of copy pasting into it.
With no issues. How do I unprotect. Please advise.

Microsoft 2002 is in use here.

Thanks.