iOS app won't run on device any more under iOS 12: Unrecoverable CT signature issue

Question

I have an app that crashes immediately when starting under iOS 12 on a device.

The console shows the following error:

kernel AMFI: 'AppName' does not pass CT evaluation, result: 0x80008

kernel AMFI: Unrecoverable CT signature issue, bailing out.

The app runs fine in the iOS 12 simulator, and it also runs just fine on devices with iOS 11 or iOS 10. (I can even distribute the app through enterprise OTA on older devices just fine!)

What did iOS 12 change? What is this "CT signature"?

Many thanks in advance!

Answer 1

I'm not sure if this will fix it for everyone, but I had the exact same problem and it solved the problem for me. In Keychain Access, I set the trust settings to "Use System Defaults" for the following certificates:

• Apple Worldwide Developer Relations Certification Authority
• Developer ID Certification Authority
• iPhone Developer: {email}
• iOS Distribution

Some of them were set to "Always Trust" before, and changing it seemed to resolve the issue. When running Xcode however, it initially still did not work, so I cleaned the build and restarted Xcode, and the application finally launched.