Choose whether dragging copies or moves a file in Finder

Why it happens

Finder guesses what you want from where you drop the file. Dragging to another folder on the same disk moves it, so the original disappears from where it was. Dragging to a different disk, such as a USB drive, makes a copy and leaves the original in place.

How to fix it

1. Open Finder and show the file you want, then open the place you're sending it to. Press Command-N for a second Finder window if that helps.

   Finder

2. To copy instead of move, start dragging the file, then press and hold Option. A green plus sign on the pointer means it will be copied. Let go of the mouse or trackpad first, then the Option key.

3. To move a file onto another disk instead of copying it, hold Command while you drag. The green plus sign goes away, and the original is removed once the move has finished.

4. Check both places. With a copy, the file is in both folders. With a move, it's only in the new one.

Still not fixed?

1. Prefer the keyboard? Select the file and press Command-C, open the new folder and press Option-Command-V to move it there, or Command-V for a copy. Holding Option in the Edit menu shows Move Item Here.

   Finder›Edit›Move Item Here

2. Moved something by mistake? Press Command-Z straight away, or choose Edit > Undo, and Finder puts it back.

   Finder›Edit›Undo

3. For a copy in the same folder, select the file and press Command-D, or choose File > Duplicate.

   Finder›File›Duplicate

4. If nothing will copy onto a drive at all, select the drive and choose File > Get Info. If it says you can only read, the drive is formatted in a way your Mac can't write to, or it's locked.

5. If copies stop part way with an error every time, back up what you can and check the drive with Disk Utility. If the Mac's own drive keeps failing, contact Apple Support or a repair shop, because it may be a hardware fault.