提示

Development cannot be enabled while your device is locked.

 

分析原因：

由于第一次连接MAC时，在iOS设备上点击了"不信任"选项，所以XCode 8不能访问手机，所以才出现这个问题

 

参考

https://support.apple.com/en-us/HT202778

 

解决方案

Change your settings for trusted computers
Your device remembers the computers you've chosen to trust.

If you don't want to trust a computer or other device anymore, change the privacy settings on your iPhone, iPad, or iPod touch. 
Go to Settings > General > Reset > Reset Location & Privacy. 
Now when you connect to formerly trusted computers, the Trust alert will ask you whether you trust that computer.