Applies to Xcode 7.3.1
t = 28.69s Find: Descendants matching type Button
t = 28.71s Find: Elements matching predicate '"Setup" IN identifiers'
t = 28.79s Assertion Failure: UI Testing Failure - Failure getting list of active applications: AX error -25205
This problem has shown up again and it appears that only solution is to reboot. I orginally report this problem in relation to Xcode 7.3 running on OS X 10.10.x. My original bug report 25955613 was marked duplicate of 25749709 (Closed) as of April 29, 2016.
The problem appeared to get worse after OS X 10.11.5 (15F34) update and shows itself on both simulators and hardware.
It would be interesting to know if anyone else is seeing this or has a workaround. Rebooting each morning and re-setting up the test environment takes a lot of time.