Many of you already know this…
If you drag files on your internal/main hard drive from one folder to another on the same hard drive, all you are doing is moving them. (The same applies to any hard drive as long as you are dragging to a location on the same drive) If you want to create a copy in the location you are dragging to instead of moving the originals, simply hold down the OPTION key on your keyboard before you release the mouse button. You’ll see the cursor change to include a green circle with a white plus sign. This indicates, “make a copy”.
But how many of you knew this?
If you drag files that are on your internal/main hard drive to an external hard drive attached to your computer (or the other way around) this copy process is the default behavior and you’ll see the green circle with the plus sign automatically. However, if you want to move the files from one drive to another, and not copy them, hold down the APPLE key (also known as the COMMAND or Splat key). This can save you from copying the files and then going to their original location and deleting them.
I know I’m not the first one to discover this. Don’t get up uppity. But I bet many people didn’t know it or had forgotten.