Solved - Formula Calculation Mode - Inadvertently Changing To Manual

I open and close a lot of different spreadsheets on a daily basis. Somehow some of these seem to get set to manual calculation mode.

The ones that are created by someone else and get passed around from coworker to coworker don't surprise me much, but sometimes spreadsheets that I have created from scratch and have not shared with others somehow get set to manual mode.

Is there a keyboard shortcut that I may be inadvertently using that switches you to manual calculation mode? Any other common causes for this?

Are there any steps I can take to help ensure all my spreadsheets stay in automatic calculation mode?

Thanks, Spence