Updating Continue to Sell when out of stock field

Hi, I currently have ~30K products in my store. All were created via upload and have defaulted to have the Continue to sell when out of stock tickbox checked. I want to uncheck this tickbox for all products without having to do them either individually or unticking them all in the bulk edit function (ideally, I’d like to do this using an upload). Also, how do I change the default so any new products are created with this tickbox unchecked by default.

Any help would be extremely appreciated

Thankyou so much Wo. You have saved me a world of dramas.

Really appreciated your help :grinning_face: