I upgraded Xcode to version 4.5. Now all of the preferences are reset back to factory settings - editor fonts, colors, etc - but this is not my biggest concern.
It seems the iOS SDK 5.1 I was targeting is now gone. In project's build settings I can only choose Base SDK between "Latest iOS (iOS 6.0)" and "iOS 6.0". Is it possible to recover the previous installed SDKs?
Download from this link, all sdks should be here. Some nice guy made it