So I am still having this issue in 2021. I have seen the solution and it does not apply to me. I have 30GB free and a 1TB external hard drive will 100% of the space free. How the f can I download xcode? Really Apple, do you have to make all your software so hard to operate and a headache to deal with. I never use Apple because of this and now that I need to program in Swift I have to and run into all kinds of verbose errors when trying to install the correct software. How can I download xcode to my external HD? Apple if you're reading this you make POS software.