When deploying the application to the device, the program will quit after a few cycles with the following error:
Program received signal: \"EXC_BAD_ACCESS\".
Even another possibility: using blocks in queues, it might easily happen that you try to access an object in another queue, that has already been de-allocated at this time. Typically when you try to send something to the GUI. If your exception breakpoint is being set at a strange place, then this might be the cause.