WatchOS 2: “Cannot Install Watch App” “Error Launching 'TestApp WatchKit App Extension'”

Question

I am getting a AlertView popup error on iOS every time I try to install a watchOS 2 app in Xcode 7 beta 4:

Cannot Install Watch App<

Answer 1

In my case, the problem was solved with these process.

1. Back version control (git) to the commit that doesn't have Apple Watch extension.
2. Build & run iPhone app.
3. Re-back to the latest commit and build & run.