Xcode can't install WatchKit App:"App installation failed Could not connect to the device."

Question

The Watch paired with my iPhone is shown as the run destination, so I think it's connected. However the WatchKit app can't be installed on the watch.

watchOS 5.1.3 (S4) iOS 12.1.3 (iPhone 7)

Here's the screenshot of the alert:

I've tried many options but none of them work. 1. repair the watch, 2. clean the build, 3. delete the Derirveddata directory

The app is a newly created project which has no custom code.

What could be the possible season that the app can't be install onto the watch as it should?

Thank you in advance.

Answer 1

There seems to be no reliable fix, and this has happened for me since 2017. A commenter here said it's probably been around since the beginning of WatchKit. If anyone experiencing this could file it in Feedback Assistant (please run xcrun xcdevice list when in the bugged state) that would be greatly appreciated, so that it rises on Apple's priority list and attached logs perhaps help them fix it.

Answer 2

Turning WiFi off on your iPhone should make it work... at least until Apple fixes the root cause of this issue :/