I am on MacOS Sierra 10.12.3. I have several updates pending in the App Store app. When I try to load them, I get asked to log in. However, the e-mail address that is pre-populated and not editable is an old one that I do not use anymore as my Apple ID. I have a new Apple ID and I am even logged in with that one on the store.
What happened is that I setup this machine using a backup which still had the old Apple ID. For several reasons, I could not log in to the old Apple ID account anymore and created a new one. It seems my machine cannot forget about the old one. I deleted it in the accounts system preferences already.
Even when I log out of the App Store app, it still asks for the password for my old ID. Is there any cache file which I can delete to completely remove the old one?