If you find yourself suffering from the message A signed resource has been added, modified, or deleted every time you attempt to run your app on-device I hope I can save you some trouble.

This tends to happen to projects with extensions and the culprit appears to be CocoaPods. Somehow frameworks relevant to the main app were being copied to the extension's build folder during the signing process, then they were pruned after. That made iOS very, very angry and it refused to launch.

If you are curious, the console hasn't been removed from the Devices window in Xcode, it's just hidden by default. If you click the reveal button at the bottom of the Devices window you can see it. That's where I finally tracked down the real error - complaints about missing .framework files in the extension's .appex folder but for frameworks that were never associated with the extension's target. Exactly why this is happening must wait for another day, I have a watch app to get out the door*.

* Never stop shipping; to hell with the money and the marketing. If its been too long since you've written an app from scratch and shipped it then get out there and ship it.