回答: please see inside 由 windstar 于 2018-07-15 18:48

We can see that :
1) In your "/" file system, you have 17309800 available, that is more than 8.6G, so "Mac OS" should not say "Disk is ful
l" (yet -:)
2) /Volumes/1TB contains almost 1TB of free space.

Now what you can do is :
a) Start "Finder" application, and delete anything you don't need in "Downloads" folder

b) Start a terminal, and type
   sudo su -
   You should see a prompt "#", meaning you are super-user (root)
   Now type two commands :
   mkdir /Volumes/1TB/Downloads
   chown xinge  /Volumes/1TB/Downloads

c) If you use Safari as browser, go to
   Safari->Preferences->File Download Location->Other 
   and choose /Volumes/1TB/Downloads

d) If you use Chrome as browser, go to
   Chrome->Preferences->Advanced->Downloads->Location Change
   and choose /Volumes/1TB/Downloads

If everything goes fine, you are good to go.