FWIW, I have yet another solution... I used Console.app - system.log; Clear; launch and attach and noticed I got this line: May 14 14:35:26 my-mac Photos[30591]: objc[30591]: Class _NSZombie_NSPathStore2 is implemented in both ?? (0x7ff33ec26e30) and ?? (0x7ff34ed330f0). One of the two will be used. Which one is undefined. This stack overflow solution - https://stackoverflow.com/questions/34074305/class-nszombie-xxxxxxx-is-implemented-in-both-and did the trick: NSZombies is turned on. Go to product - scheme - edit scheme (CMD+SHIFT+.) and under run - diagnostics uncheck "Enable Zombies".