If you’re experiencing the error “An App ID with Identifier ‘com.teachyourselfios.Welcome’ is not available” when trying to install the Welcome app on your device, the fix should be simple (and wasn’t required until recently).
- Click the Welcome project group in Xcode.
- Make sure that the Welcome target is selected.
- Change “com.teachyourselfios.Welcome” to another string of your choosing.
The problem is that Apple knows that I (a registered developer) have used that string already to compile the application. When you attempt to use it, it sees it as a conflict – even though the app in question has never been submitted to Apple for App Store processing. Sigh.