Just got my shiny new Mac Book Air 13″ inch core i7 and downloaded XCode 4.2 from the AppStore.
When I tried to look up any class reference from the XCode editor, I got a login form inside the document window, and after I entered my Apple ID, it shows:
“You do not have access to this resource based on your membership.”.
It seems ridiculous that I need iOS membership to access documentation as this is not the case previously; and iOS 5.0 has been released for a while now, that means shouldn’t have NDA restriction on the beta documentation.
Magically the problem was fixed by itself when I went to Xcode | Preferences… | Downloads | Documentation and click Check and Install Now.
The download started again. (I swear that I have downloaded the same set of documentation before.)
I am not alone with this problem.
See http://forums.bignerdranch.com/viewtopic.php?f=148&t=3497
Thank you for posting this fix!