For reset Xcode to factory settings in the logged-in user, run these commands in Terminal:

> defaults delete com.apple.Xcode
> rm -rf ~/Library/Application\ Support/Xcode

At one point in the process it opted to remove the Xcode developer tools and start the configuration from the beginning. Which leads to the tip: should you ever find the need to remove Xcode, run the following from within a terminal window to make it happen:

> sudo /Library/uninstall-devtools –mode=all
is the directory where the tools are installed. For typical installations the full path is /Developer/Library/uninstall-devtools