In xcode 4.2, sometimes when you\'re going to run your ios proj on simulator, the status windows says \"Attaching to myapp\", and just gets stuck there... until you cancel.
Now,
Rebooting works for me, too, but this shouldn't be necessary. I'd recommend filing a bug at bugreport.apple.com. You can duplicate the one I created - the more it's duplicated, the more likely Apple is to fix the problem.