How to purposefully open an Excel file as "Read Only"

Open a file as a copy


When you open a file as a copy, the program creates a duplicate of the file, and you look at the duplicate. Any changes that you make are saved to the copy. The program gives the copy a new name. The default is to add Copy (1) of to the beginning of the file name.


Click the Microsoft Office Button , and then click Open.

IMPORTANT If you don't see the Microsoft Office Button , click Open on the File menu.

Keyboard shortcut To display the Open dialog box, press CTRL+O.


In the Look in list or Navigation pane, click the folder, drive, removable media (such as flash drive, CD, or DVD), or Internet location that contains the file that you want to open.


Click the file that you want to open a copy of.


Click the arrow next to the Open button, and then click Open as Copy.

NOTE When you open a file as a copy, a new copy of the file is created in the folder that contains the original file.


Open a file as read-only


When you open a file as read-only, you are looking at the original file, but you cannot save changes to it.


Click the Microsoft Office Button , and then click Open.

Keyboard shortcut To display the Open dialog box, press CTRL+O.


In the Look in list or Navigation pane, click the folder, drive, removable media (such as flash drive, CD, or DVD), or Internet location that contains the file that you want to open.


Click the file that you want to open as read-only.


Click the arrow next to the Open button, and then click Open Read-Only.

Source : https://support.office.com/en-nz/article/Open-a-file-ac57f07b-187f-45f2-a641-8a3d4ca28764#bm3