Anyone has experienced this problem?
Yesterday I still can run my app in simulator but now I cannot run my app since Xcode prints this error in console:
error: failed to attach to process ID <ID number>
I have tried to reinstall, do this post and create new project but returns no luck.
Anyone can resolve this issue?
I use Xcode 4.5 Preview 2 and try to run iOS simulator 6

Resetting the content and settings in the simulator worked for me. This is available in the “iOS Simulator” menu.