Got a question and hope people here can answer. Thanks. Using the iPhone 7 plus which was synced using an older computer. The problem appears when trying to sync it with a new Mac laptop. When the phone was first plugged onto the laptop and iTunes was opened, there wasn't any apps on the laptop and the syncing process would complete without having anything happen to the phone. Therefore, the laptop was authorised with the Apple ID and then all apps found in the "purchased" was downloaded to the laptop. Clicked "update" for one of the many apps that needed to be updated and the "sync". An error message that says "The iPhone could not be synced because this computer is no longer authorised for purchased items that are on this iPhone" appears. Called Apple support and the person says that it may be because there are apps on the iPhone that may have been downloaded using another Apple ID. Here is the question: 1) What would be a good way to sync the iPhone with this new laptop? 2) When syncing the phone with a new laptop, does all apps needs to be erased from the phone and then selected and installed again using the iTunes on the new laptop? 3) Is there a way to find the app on the phone that may have been downloaded using another Apple ID? The Apple support says that the sync would only work when the same Apple ID is used for ALL apps on the phone.