When I opened the app store app on Macbook Pro, it asked me to login in a pop-up box. The strange thing here was: The user ID field was disabled to edit and it had a pre-filled email address which is unknown to me. So that pop-up box had only password field enabled to fill in for an unknown email address.

Is there a way to track where that email was coming from? Does this mean the Macbook Pro device is hacked? What are some measures that can be taken to prevent this?

I have always kept the device locked and secured from public wifi.


If you bought the Mac used, this could be the AppleID of the person who sold it to you. You should be able to find an option in the Store menu (Store —> Sign Out) to sign out of that AppleID. You’ll be able to sign in to your own ID after that. Be aware that apps that were provided with the Mac may need to be re-purchased or downloaded again to associate them with your ID, or to be able to use or update them after signing out.

  • It was a new purchase. – GC 13 Mar 19 '19 at 21:52
  • Did you restore from a backup or copy over any apps from an older Mac? If apps from another device were installed they might trigger this as well. Did anyone help you set it up? Can’t think of any other reasons this would happen! – dr.nixon Mar 21 '19 at 1:41
  • No. It was a new installation for each app installed on this device. I set it up by myself. – GC 13 Mar 22 '19 at 14:55

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