I've purchased a 2009 iMac, bought Mountain Lion from the App Store and performed a Clean Install, but when I open up the App Store, I still see messages to update apps that the previous owner had installed (I don't own them), furthermore, I'm prompted to sign in with his Apple ID in order to download these updates.

I thought that when I did a clean install, all of his information should have been deleted. Am I wrong? How could I get rid of this problem?

  • 2
    Can you name one app that's still tied to the previous owner? All signs point to an incomplete erase before you reinstalled the OS.
    – bmike
    Commented Apr 18, 2013 at 13:40

3 Answers 3


Now that you are on Mountain Lion, you can boot to recovery mode and re-erase the entire Macintosh HD (or whatever name the OS volume has). Perhaps your definition of clean install didn't actually clean the offending apps or you are connecting another hard drives with apps purchases from the previous owner's account. (The app store will offer to update any apps it sees, not just the ones in /Applications)

Here is a long article on recovery, but details at the bottom show explicit steps you would take to prepare an external drive to install Mountain Lion. You will want to perform those steps from Disk Utility when booted in recovery mode.

Note, that if the previous owner had "redeemed" the iLife apps (as described in the article above), those will remain tied to their account so for you to install them, you will need to purchase iPhoto, iMovie and GarageBand since they are not part of the Mountain Lion software upgrade you purchased, but after a clean wipe, you won't have those applications and could only see them if you had a copy somewhere other than the wiped drive or signed in to see past purchases for that previous account.


I thought that when I did a clean install, all of his information should have been deleted. Am I wrong? How could I get rid of this problem?

Yes and no. With a clean install you erased informations stored on hdd/ssd but when you finishes install and connect to internet your mac contact apple's servers and try to restore some info (if previous owners enabled backup on iCloud with same apple ID you are able to restore bookmarks, contact, etc). In order to verify your identity Apple's servers get info from your mac (serial number) and match with last apple id registrated in they're database. That's the reason you're prompted for previous owners apple id. You can easily get rid of this by logging in with your Apple ID and data in Apple's db will be updated.

  • This would be an egregious leak of personally identifying information if Apple altered the new owner of a Mac the old owner's email address. I have never seen this happen and suspect another cause of the alert such as an incomplete wipe or the presence of paid apps from the previous account on an external drive or restored from a backup.
    – bmike
    Commented Sep 6, 2013 at 22:30

May I give you some suggestion. you should bring your imac to one of the authorized replay center from apple . and explain to then your situation . you should bring your buying document . let them fix it for you . it 's will be a fee that you have to pay.

I also bought a imac and it is happening to me too. my case is quite bad . the previous owner intents to lock my imac after you brought it home for few days . even i erase everything , before i start using it . they lock in the EFI firmware and they look with passcode . you couldn't get in unless you pay them more money . ....... My case is a very high price lesson . shouldn't buy a second hand imac or any used apple products

take my advice .. the security in Mac is very secure

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