I have updated the xcode 4.3.2 to 4.5 . I have mac version 10.7.3. dmg file which i have downloaded is not recognized by the mac . So I have to update the mac version also so from which version mac supports Xcode 4.5 ?
See this link. It is clearly mentioned that `Requirements: OS X 10.7.4 or later. You just need to do a software update by clicking the Apple menu.