Set 'Read Only Recommended' in Excel
The option to give people a prompt that open an Excel spreadsheet recommending them to open it as ‘read only’ is in a slightly different place in Excel 2007 and Excel 2010 than it was in earlier versions. Follow the steps below to find it.
Step 1: Choose File -> Save As
Step 2: Enter a filename, and click on ‘Tools’, just to the left of the Save button. Then select ‘General Options…’.
Step3: In the box that opens, select the checkbox next to ‘Read-only recommended’ and press OK.
Step 4: Then save as normal. You will see the following prompt the next time you open it.