This is Emacs 25.1 installed via MacPorts on macOS 10.12. This happens randomly but very frequently. I'm told that a reliable way to reproduce it is to resize the window while mashing C-g. On Wed, Oct 12, 2016 at 12:44 PM Jean de Largentaye wrote: > crashing in org.gnu.Emacs in deliver_fatal_thread_signal • Uncaught > Exception 'NSInternalInconsistencyException': nextEventMatchingMask should > only be called from the Main Thread!terminating with uncaught exception of > type NSException : at com.apple.AppKit in -[NSApplication(NSEvent) > shouldBeTreatedAsInkEvent:] + 0 > > Apparently, calling nextEventMatchingMask from a background thread is > risky, and this has been made an assert as on 10.12, hence the crash. >