MS Excel - Make workbook read only

There are multiple ways to make your MS Excel file read-only. The method shown below is the easiest and the best way that I have found. The goal is to prevent accidental changes. It is not to encrypt the content of your MS Excel file. Users can still save changes by creating a new copy of the workbook.

1. Open your MS Excel file.
2. From the File menu, click on Save As.
3. Click on the Tools button and select General Options....
   
4. In the Password to modify input field, enter a password and click OK.
   
5. After your password is set, every time your MS Excel file is opened, the user will get the following pop-up.
   
6. Users can still view the content of your workbook but only in read-only mode.