Failed to acquire termination assertion when installing placeholder. What does it mean?

Question

I am getting this error in Xcode 9 beta . What does it mean? Attaching snapshot for the same.

Answer 1

The problem seems to be that Xcode 9 Beta does/can not close the iPhone app if it is open on the simulator when the app is built and run (which it used to do). Simply closing the app on the iPhone simulator (shift-command-h) seems to do the trick. Another option is to restart the simulator. Hopefully Apple will fix this issue soon.