How to remove Protection from Excel 2011

•  Make sure a copy of your excel file before doing any changes
• Right click and rename your excel file to example.xlsx to example.xlsx.zip

• Double click on zip file and go to xl 

• Copy the worksheet folder from zip to another path ( like on your Desktop or Document)

• Then go to the worksheet folder

• Right click and open the sheet file in note pad

• Press ctrl + F and type protect then find it.
• Remove the following script from sheet file.
• Make sure it will be under <to>.

• Do the changes in all your sheet files.
• Then replace the worksheet folder in your zip file.

• Now rename your file .zip to .xlsx
• Open your excel file and check that your protection is removed.