I have 2 machines. On one of them I updated to xcode 4.5, but doing so uninstalled my iOS simulator for 5.1.
I'm hesitant to update my other machine as I have a project that requires the 5.1 simulator.
Are my assumptions correct or did I do something to remove the older simulator without knowing?
You can redownload the simulator in the Xcode preferences.
joe
Download Xcode 4.3.3 for lion and open the dmg, and click and show package contents,and copy the Contents\Developer\platforms\iPhoneOS.platform\sdks\iPhoneOs5.1sdk folders into your xcode4.5 Contents\Developer\platorms\iPhoneOS.platform\sdks folder, and it works
来源：https://stackoverflow.com/questions/12503575/will-installing-xcode-4-5-remove-ios-simulator-5-1