Turn off auto update on opening

I have a complex workbook with lots of links which takes 4-5 minutes to open. Until recently, on opening the workbook I got the prompt asking whether I wanted to update or not and often I want not to update - just to add data.

I checked the update options in Edit, Links and found them set to Automatic for every link, while the Manual option is dim. Is there something I have done elsewhere that has changed this option? How can I get the "update or not" prompt back?

HELP!!!

I found the answer. Somehow I had managed to turn off "Ask to update automatic links" on the Edit tab in Options.