I ran out of space on my external hard drive so I selected some folder file and pressed command-delete on my keyboard. They files looked as if though they were deleted but I notice the available space did not budge. I knew right than it was time to whip out the terminal to force the hard drive in to submission.
1) Type these command into Terminal window. MAKE SURE TO replace “disk” with the name of your external drive. If you have a problem creating a path to your external hard drive, type “cd” than a space and drag the icon of your hard drive to the terminal window. A path will be filled in automatically.
2) Type out the remove command on then hidden trash directory.
sudo rm -rf .Trashes
3) It will ask you for your password. You will not see your password as you type for extra security. Once you are done, press enter.
If you have a lot of files that needed deleting (ex: over 20GB) you may notice a dalyed response. If so, just keep an eye on the drive’s avalible memory and you will notice a gradual increase of space right before your vary eyes.