Mac App Store updating problem I've recently upgraded to Mac OS Yosemite, but the App Store won't let me install app updates. It says "Sign in to the App Store to download apps." I'm already signed in though, and the sign in box that pops up won't let me change the Apple ID to mine. I've restarted, logged out, logged in again, and it still won't work. I'd assume that this is because they were installed with a different Apple ID. Can I uninstall and reinstall the apps without buying them/losing data? Will installing the apps myself again without updating get the updates and stop telling me about them? Or is there any way to install these updates? Also, they're for the Apple apps like iPhoto, iMovie, and GarageBand, but nothing other than those Apple ones.

Thanks!
You can log out from the App Store after you click "Account" at the Quick Links sidebar (inside the "Feature" Tap)
  You can log out and change the Apple ID inside the OS X settings
  You need to log in with the Apple ID you bought the apps with
  You can delete certain apps and keep the files. Like iPhoto keeps its Library inside the Pictures folder in your Home directory 
  You have to buy the Apps again if they cost money if you want to update them with your other Apple ID