I have recently had to reinstall OneDrive onto my Mac. Now, whenever I open a Word document that is stored in OneDrive is get an annoying popup starting with "Co-author in the Web app" and asking me to switch to a subscription version of Office. I paid for my version of Office outright, don't want to pay again and I want to get rid of this popup.

When you click the "help" button, it says "You can disable these notifications by going to File > Options and selecting Always use this app to co-author on documents" but when if I click on File in my version of Word it doesn't give me "Options/Always use this app to co-author on documents".

How do I get rid of the pop-up, please.