Can't update Xcode even with 19gb free space
You might be close, but I downloaded from the developer website and I had  freed ~22 GB.

Try freeing up some more, like cache or movies you have watched, or software you don't use.


How can I figure out what&#39;s slowly eating my HD space? 
Reduce size of the Xcode application
Gigabytes of disk space shown as hidden space in DaisyDisk