Xcode beta 6 iOS 8: Simulator not working

I cannot launch the simulator successfully. Once I launch the IOS Simulator this error appears:

"Unable to boot the IOS Simulator."

Following the IOS Simulator error, I then get an error from Xcode reading:

Unable to run app in Simulator
An error was encountered while running (Domain = DTiPhoneSimulatorErrorDomain, Code = 2)

UPDATE:

This might sound silly but I went to Xcode/preference/Downloads with intentions of seeing a IOS 8.0 Simulator but there was none. Could this be the problem? Am I suppose to have a IOS 8.0 Simulator? If so can someone direct me how to get it? Also, under the "Downloads" tab in Xcode preference I do see IOS 7.0 and 7.1 Simulators and both work fine with Xcode 5.

Solution 1:

the trick is, to select the right command line tools! just select it here

reboot(!) and everything is fine again :-)

Solution 2:

Ok It's known problem. Do you see simulators list? If not

Goto Xcode Menu -> Open Developer Tool -> It will open a simulator in your Dock -> click on simulator then go to Simulator Menu: Hardware -> Device -> Manage Devices. Add needed simulators. Always try to run your app with different simulators.someone will work.

Solution 3:

Restart your Mac. I just had that exact error after installing Xcode 6 beta 7, literally the only thing I did in response was reboot my Mac and now the iOS 8 simulator is working.

This error is common if you update Xcode without restarting afterwards.