App Store on iOS keeps asking for another user's iTunes credentials

I recently helped a friend activate her iPhone 5. She used to have an iPhone 4S which I helped her do a backup on my Macbook. After backing up her iPhone 4S, I restored her iPhone 5 with the backup. Because her SIM card was not the correct size, I used my own SIM card to activate the phone as well.

But now there is a very weird issue where if she downloads certain apps from the App Store, it would ask for my Apple ID credentials instead of her's. I tried signing out of the App Store and having her sign in. But every time I download a certain app, it keeps asking for my credentials. Very strange.

Any one know of how to fix this?

PS: iCloud is also signed in with her credentials.

Solution 1:

• When an iPhone is restored from a backup, it gets as much data as is can locally. Any app data is stored in the backup, but the apps themselves either have to be synced from a local iTunes (preferred) or downloaded.

• When an iPhone is synched with iTunes, by default all apps on the iPhone are copied to the iTunes library, assuming iTunes is registered with the same Apple ID as they were purchased with. I think.

• iOS app files are registered with a specific Apple ID, and without this same authentication, there's no (easy, non-jailbreak) way to use the app with another Apple ID.

So, when you restored your friend's iPhone with your computer, rather than download all of the apps from the iTunes servers, it copied as many as it could from your computer. These apps are linked to your Apple ID, so in order for your friend to use them her iPhone would need to be registered with your Apple ID.

The solution: Your friend can back up her iPhone to iCloud or another computer (make sure, if so, that the offending apps are deleted from the iTunes library after synching) and restore it again. This will definitely keep her data from the other apps, and probably from yours as well. Alternatively, she can delete all of yours and re-download them from the App Store, which will definitely lose the data.

Solution 2:

I have found a solid solution to the problem. I once put some music on my friends phone and you have to sync to do that and when you do you add his apple ID to your computer. What has happened is that somehow I downloaded an app and he had also and the app is backed up to the icloud under his apple ID. The fix is to

1. first sign into itunes account for the account that is the wrong one and go and then go to help and view account info. Then down to itunes in the cloud and on the right click on manage devices, then remove from the computer you first synced the wrong account to. Next comes the tedious part.
2. sign into itunes using the correct account and then go to the apps section, specifically the update all section. Next right click on your apps and then view info, you should see which acct the apps were originally purchased/downloaded into your phone and also the ones that were purchased/downloaded to the wrong acct. NOW delete those apps not synced to the right itunes ID and select delete from computer also. After removing the problematic apps, update them, then sync the phone and all should be good.