I have been trying for months to figure out why my Excel files change from Automatic to Manual calculations at random. The file will be working fine, and then change to manual calculations. It doesn't happen all the time, but if I unhide or add a new workbook it will change. I have tried everything I have read and nothing will correct this problem. What can be done? I'm at a total loss, and have spent more time on trying to figure this out than I care to admit. Our office IT Department can't even figure it out. Please provide a solution.