Q: Did Xcode5.1.1 get rid off the offline documentation? For some reason, I reinstalled my MacBook last night, and downloaded Xcode 5.1.1 from the Mac App Store. I was very surprised to find that my Xcode can not download documentation from Apple Dev center, I don't mean when I clicked the download link, it told me "Fail to download" or other words, it just didn't there, my Xcode Preferences -> Downloads -> Documentation has no list or anything else.

Did anyone know why or ever met the same situation like me?

A: Well.. I have the same problem, unfortunately. I'm trying to install docsets for few days already. It seems like an error in apple's docset-index.dvtdownloadableindex file. Look up in Console.app for an Xcode error:
[MT] DVTDownloadable: Failed to refresh index from
 <https://developer.apple.com/library/downloads/docset-index.dvtdownloadableindex>: Error...

...and so on.
I went to https://developer.apple.com/library/downloads/docset-index.dvtdownloadableindex described in the error message. I found there 3 links to the docsets I need and downloaded .dmg files. There are 3 .pkg files, i've just installed all of them and copied 3 docsets from / (the root, Macintosh HD) to /Applications/Xcode.app/Contents/Developer/Documentation/DocSets with replacing existing files. And these docsets have finally appeared for offline. 
Okay, steps for getting offline docsets:


*

*Download these 3 .dmg files (please, delete spaces before .com,
my reputation isn't high enough to post many links):
iOS : adcdownload.apple.
com//Developer_Tools/ios_7_doc_set_13v23/0918569a.dmg OS X :
adcdownload.apple.
com/Developer_Tools/os_x_v10.9_doc_set_13v23/0918568a.dmg Xcode :
adcdownload.apple.
com/Developer_Tools/xcode_5_doc_set_13a23/0918567a.dmg

*Open downloaded .dmg files and install .pkg (it just copies .docset
files to /)

*CHECK FILE NAMES before copying docsets! They must match existing files in DocSets folder! (mine were the same but the Xcode .docset file name)

*Finally, move DocSets from /folder to /Applications/Xcode.app/Contents/Developer/Documentation/DocSets

*Restart Xcode


I hope Apple will fix it soon... As I can see, the problem is in the beta docsets described in the end of file (WWDC 2014 Beta section). However, I tried with Xcode 4.6.3 and everything worked fine. I tried everything (including reinstalling OS X) but that is the only way I've made offline documentation work. 
Hope it helps you! Good luck!
Yours, 
Andrew
