So I've just updated to macOS Sierrra beta 4 (16A270f) and I've installed Xcode beta 4 (8S188o).
But now it won't let me install "Guides and Sample Code" ending after the download of 1,13 GB with the following error message:
"Could not download and install Guides and Sample Code, an Unexpected error has occurd while moving the files to the final location"
So any help with this would be nice...
found the answer:
1. Stop or otherwise end the failed download and quit Xcode.
2. Manually navigate to ~/Library/Developer/Shared/Documentation/DocSets/ (~/Library/ = in your user folder)
3. and remove "com.apple.adc.documentation.docset". Leave all other files in that folder as they are.
4. empty trash.
5. Re-open Xcode and installing Guides and Sample code again should work now.