Move vs Copy on a Mac: What Happens With External Drives, USB Sticks and Network Shares
Quick answer: On a Mac, dragging a file within the same disk moves it, and dragging it to a different disk (an external drive, USB stick or network share) copies it, leaving the original behind. Hold ⌘ while dragging to force a move, or Option to force a copy. With the keyboard, ⌘C then Option+⌘V moves the item.
This catches out people from Windows, where the rules differ. Here is exactly what happens in each case.
The rules
| Action | Same disk | Different disk or network share |
|---|---|---|
| Drag | Moves | Copies |
| ⌘-drag | Moves | Moves |
| Option-drag | Copies | Copies |
| ⌘C then ⌘V | Copies | Copies |
| ⌘C then Option+⌘V | Moves | Moves (copy, then delete) |
Why a move across disks is slower
When you move a file to another disk, Finder cannot just change a pointer. It copies the file to the new disk and deletes the original only after the copy finishes. For large folders on a slow USB drive or a network share, this can take a long time, and it needs enough free space on the destination.
Moving to an external drive safely
Make sure the drive is formatted for the Mac, or for both Mac and Windows if you share it.
Hold ⌘ while dragging, or copy and use Option+⌘V.
Wait for the progress bar to finish before unplugging, and eject the drive from the sidebar.
If the transfer is interrupted, check that the destination copy is complete before relying on it.
Network shares
Network shares behave like other disks: a move is a copy followed by a delete. If the connection drops halfway, you may have a partial copy at the destination and the original still in place. Check both before deleting anything.
A real Cmd+X for files
FileCutPaste lets you press ⌘X, open the other disk and press ⌘V, with Finder doing the move. See How to Use FileCutPaste app to Cut and Paste Files, Folders and Images on Mac.
FAQs
Does dragging to an external drive move or copy?
Copy, unless you hold Command.
How do I move a file instead of copying it to a USB drive?
Hold Command while dragging, or press Option+⌘V after copying.
Is it safe to delete after copying?
Only after you have checked the copy opens correctly.