安装完xcode6.1后，将其改名为Xcode6.1.app，再移动个位置，启动模拟器，问题来了：

Unable to boot device in current state: Creating

解决办法：

You will need to delete this device from your simulator and recreate it.

From inside the iOS Simulator application menu, choose Hardware > Device > Manage Devices

In the Simulators list on the left, select the device that is unable to boot and press the delete key

Now use the + in the bottom left to add a new device with the same hardware / OS configuration.

转自 http://*.com/questions/26480836/unable-to-boot-device-in-surest-state-creating

另外还需注意：

Xcode->Preferences->Locations->Command Line Tools的位置重新选择下