Mac – re-purchase an app with a different apple ID

To make the AppStore forget the old credentials with which an app was downloaded, remove the _MASReceipt directory in the app itself.

To do this:

1. Open Finder and navigate to Applications.
2. Ctrl+Click the application and choose "Show Package Contents".
3. Expand the Contents directory and click the _MASReceipt directory to select it.
4. Type Command+Delete to delete the directory permanently---you will be prompted for your credentials since this is a protected file.

Quit and restart AppStore, then find the application. The button should now say "Free" or "Install" instead of "Update". Clicking it will update your app to the latest version, doing so as the currently logged-in Apple user.

This can also be a temporary issue and it can clear up over time once the servers recover from some overload conditions.

Contact Apple billing support and/or the place you purchased the Mac to see if they can assist with resolving the server side issue. The OS updates are tied to the serial number, but the iLife apps go through a redeem process where the hardware identifier and your Apple ID get bond together, and the Apple servers apparently think a different account is set up for those apps on your Mac.

I'm assuming you have no idea and don't recognize the other Apple ID and it wasn't just a case of you accidentally redeeming the applications. I'm also assuming you can sign into the account you intended to redeem these apps. At worst, Apple or the seller should be able to gift you the apps to the correct account so you can get updates going forward if you (or someone else trying to be helpful) has made a mistake.

Here is what a Mac should look like before you have "accepted" the iLife apps by opening the App Store App and signing in and choosing Purchases (command-4) from the menu bar.