[jondwillis]

Simply:

CMD+,

Locations

Derived Data

CMD+Q Xcode

Delete!!! Derived Data

Restart Xcode

Why not Clean Build Folder

  CMD+B

success!!

[ninkendo]

I have a shell alias for

  mv ~/Library/Developer/Xcode/DerivedData ~ && rm -rf ~/DerivedData &

And I use it constantly. This approach is fast because it does the actual rm in the background so I can relaunch Xcode right away.

[saagarjha]

I have a source editor extension that has no job but to clean this clean this ;)