Failed to prepare the device for

xcode 连接手机提示 Failed to prepare the device for development. Please unlock and reconnect the device.

记录一下,周一早上一来就遇到这警告,周五下班时候还是好好的,设备和xcode也没有更新,那肯定不是设置的问题,OK让我们重启电脑和手机试试,重启完毕再次连接,好了.