Re: XCTests crashing user session back to login screen

Jeremy Hughes

On 2 Oct 2019, at 16:47, Jens Alfke <> wrote:

Every time it happens, there are no logs that I can find explaining the cause. My suspicion is memory leaks in the iOS app I am testing and zombie pointers writing to memory outside of the simulator.
No, that hasn’t been possible since the OS 9 days. Every process is isolated in its own address space, and there should be no way for an application process to break other apps or your login session. What’s happening sounds like a crash of the top-level process of your login session (is it still called loginwindow?) or of the WindowServer.
Apple’s support page ( suggests that it is still possible for an application to bring down the system:

"If your Mac suspects that a particular app caused the restart, it might ask whether you would like to move the app to the Trash. Click Move to Trash, then contact the software developer to see if a software update is available.”


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