This generally means that another instance of this process was already running or is hung in the debugger

今天调试程序提示如下错误：

This generally means that another instance of this process was already running or is hung in the debugger

字面意思是此线程中已经有一个实例运行....

然后做了如下操作：

1、停止项目，重新运行，不能解决

2、重启模拟器，不能解决

3、重启xcode，不能解决

4、重启系统，解决

具体原因还在查找中.....