Remove old Apple ID Account When trying to update apps on the Apple Store I still get the account of someone who was using the computer before me:



How do I change that, it's the only place where I can't use my Apple ID account.

PS: It sounds like I stole a computer but no, my work gave it to me and the employee before me was using it with his Apple ID account and thought he removed everything.
Technically that person owns those apps.  You can remove the app, which removes the MAS receipt, and re download it while your signed into the app store.  Then it will be associated to your apple ID and owned by you.