This issue happens in my app and I don't know why, I cannot get even useful info from stack. it's all about AppKit and HIToolBox or CoreFoundation. I initially suspect it might be related to NSTimer. However I think this wouldn't cause such a crash. I am currently out of ideas and unable to provide more detailed and effective information (if I could, that would be great, and I also hope to have it). I search Apple Doc and it tell me NSInternalInconsistencyException occurs when an internal assertion fails and implies an unexpected condition within the called code. So I want to get some clues from you why I encounter such an issue. @interface MyApp () { scoped_refptr<base::SequencedTaskRunner> task_runner_; } @implementation MyApp //... - (void)start { // ... self.timer = [NSTimer scheduledTimerWithTimeInterval:60 // call every 60 sec target:self selector:@selector(logAndKill:) userInfo:info repeats:YES]; - (void)logAndKill { if (needLog) { // ... } else { task_runner_->PostTask(FROM_HERE, base::BindOnce(^() { [self.timer invalidate]; self.timer = nil; }));