Dragging files sometimes moves them, sometimes copies them, and sometimes opens them — with no obvious logic
You drag a file to a new folder and it moves. Then you drag a different file to an external drive and it copies instead. Then you drag something onto an app icon and it opens the file. Three different outcomes from the same gesture, and you never know which one you're going to get.
Why does this happen?
macOS drag behavior is context-dependent: dragging within the same volume moves the file; dragging across different volumes copies it; dragging onto an app icon opens it. Each behavior makes sense individually but the inconsistency is genuinely confusing without knowing the rules.
How to fix it
To force a COPY when dragging: hold Option (⌥) while dragging — a green + badge appears confirming copy.
To force a MOVE when dragging across volumes: hold ⌘ while dragging — the file moves instead of copying.
Watch for the green + (copy) or no badge (move) while hovering to see what will happen before releasing.
Dragging onto app icons always opens — to move/copy near an app, drop into a Finder window instead.
Discussion
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