Password Protected worksheet and workbood does not prompt for password

[priyajk10]

Hi

I password protect several sheets and the workbook in an Excel file before passing it on to my clients. When I get it back with their edits, the sheets and workbook are still protected, but clicking "unprotect" unprotects them without asking me for the password.My clients are not computer 'savvy' enough to know how to crack Excel passwords using any kind of tool. A google search resulted in the same issue posted on Reddit but was never resolved. Any help would be much appreciated.The file is an .xlsx, and I'm running Excel 2013 or Office 365. The problem clients are running Excel 2007.

Thanks.