How to Lock Unlock an Excel Spreadsheet

Locking
1. Open the Excel spreadsheet you want to lock.
2. Click the green 'File' tab on the ribbon.
3. Click the large, square 'Protect Workbook' button.
4. Select a permissions level. Choose 'Mark as Final' to make the spreadsheet read-only. This option does not require a password and only discourages, but does not prevent, editing.
5. Choose 'Encrypt with Password' if you want to prevent anyone from opening the spreadsheet without a password. Type the password in the box and click 'OK.' Excel will prompt you to re-enter the password. Re-enter the password and click 'OK' again.
6. Choose 'Protect Current Sheet' if you want to set a password for opening the spreadsheet and want to restrict editing of specific cells or areas. Enter the password in the box and click on the various items you want others to be able to do. Whatever you do not check off will be disallowed. Click 'OK' when you are satisfied. Excel will prompt you to re-enter the password. Re-enter the password and click 'OK' again.
7. Choose 'Protect Workbook Structure' if you want the structure to remain intact while allowing others to make most changes. Users will not be able to delete or move sheets but otherwise, they will be able to add rows and make calculation and style changes. Enter the password and click 'OK.' Excel will prompt you to re-enter the password. Re-enter it and click 'OK' again.
Unlocking
8. Open the Excel file you want to unlock. If it is fully encrypted such that no one can open it without a password, Excel will prompt you for a password at this point. Enter the password and click 'OK.'
9. Click the 'File' tab. You should see the word 'Permissions' written in orange; this lets you know that the worksheet is protected in some way.
10. Click 'Protect Workbook' and select the protection option that is highlighted in orange. This indicates the level of protection you used to lock the spreadsheet in the first place.
11. Enter the password to unprotect the spreadsheet. Click 'OK.' You will be able to make any edits to the spreadsheet.
12. Save the document. The next time you open it, you will not need a password.