Xcode beta 6 iOS 8: Simulator not working

Question

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

\"Unable to boot the IOS Simulator.\"

Answer 1

I saw the same issue when I installed Xcode 6 beta 6, and deleted beta 4 and beta 5. Apparently, deleting the old betas also deleted the iOS Simulator 8 versions! Putting it back from my Trash solved the issue.

Solution: Don't delete old beta software!

Edit: @Flori's solution worked. Was able to delete the old beta software, and after a complete system reboot, it worked again.