I experience an app crash in random point at the time when I force to close the app (enter to multi task screen and slide up on the app to force close). I don't see a pattern how to reproduce the crash. Usually, I do a monkey play for a short time and close the app. Then, crash will happen sometimes ( 1 out of 15 to 20 trials ). It may be easy to see the problem in low data bandwidth situation. I have run many release versions of the app to see any hint on the cause of any app feature. I have no luck, app crash can be found in all versions. Some version will popup the dialog box for crash report. Some version will crash silently. However, app log can be found in system setting > privacy > Analytics & Improvements > Analytics Data and they are more or less the same except the thread number. Part of log is attached at the end of question for reference. Based on the track stace, I have no idea where the crash is happened. Please help to provide guideline or direction how to study the problem. Exception Type: EXCCRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXCCORPSENOTIFY Triggered by Thread: 9 Thread 9 name: Thread 9 Crashed: 0 libsystemkernel.dylib 0x000000019bfded88 _pthreadkill + 8 1 libsystempthread.dylib 0x000000019bef71e8 pthreadkill$VARIANT$mp + 136 (pthread.c:1458) 2 libsystemc.dylib 0x000000019be4a644 abort + 100 (abort.c:110) 3 libc++abi.dylib 0x000000019bfb2cc0 abortmessage + 128 (abortmessage.cpp:76) 4 libc++abi.dylib 0x000000019bfa4df8 demanglingterminatehandler() + 272 (cxadefaulthandlers.cpp:60) 5 libobjc.A.dylib 0x000000019bf0be90 objcterminate() + 140 (objc-exception.mm:704) 6 libcabi.dylib 0x000000019bfb214c std::terminate(void (*)()) + 16 (cxahandlers.cpp:59) 7 libc++abi.dylib 0x000000019bfb20e4 std::terminate() + 44 (cxahandlers.cpp:88) 8 libdispatch.dylib 0x000000019beaf538 dispatchclientcallout + 36 (object.m:498) 9 libdispatch.dylib 0x000000019be57b54 dispatchqueueoverrideinvoke + 684 (inlineinternal.h:2484) 10 libdispatch.dylib 0x000000019be64438 dispatchrootqueuedrain + 376 (inlineinternal.h:2525) 11 libdispatch.dylib 0x000000019be64bf8 dispatchworkerthread2 + 124 (queue.c:6628) 12 libsystempthread.dylib 0x000000019bf00b38 pthreadwqthread + 212 (pthread.c:2364) 13 libsystempthread.dylib 0x000000019bf03740 startwqthread + 8 Thread 9 crashed with ARM Thread State (64-bit): x0: 0x0000000000000000 x1: 0x0000000000000000 x2: 0x0000000000000000 x3: 0x0000000000000000 x4: 0x000000019bfb5efc x5: 0x000000016c2de9c0 x6: 0x0000000000000074 x7: 0x000000016c2de968 x8: 0x000000016c2df000 x9: 0x7db45dbdbb09246f x10: 0x000000019bef7160 x11: 0x0000000000000023 x12: 0x00000002808c8a98 x13: 0x0000000000000001 x14: 0x0000000000000010 x15: 0x0000000000000056 x16: 0x0000000000000148 x17: 0x0000000000000000 x18: 0x0000000000000000 x19: 0x0000000000000006 x20: 0x0000000000004303 x21: 0x000000016c2de9c0 x22: 0x000000016c2df0e0 x23: 0x0000000000000114 x24: 0x000000016c2df0e0 x25: 0x00000001e5ff5a40 x26: 0x00000000000005ff x27: 0x00000001e8fda4c0 x28: 0x0000000002ffffff fp: 0x000000016c2de920 lr: 0x000000019bef71e8 sp: 0x000000016c2de900 pc: 0x000000019bfded88 cpsr: 0x40000000 esr: 0x56000080 Address size fault