Two ways the Dock loses your layout
The first is removal. Drag a pinned icon far enough from the Dock and macOS takes that as “remove this,” complete with a puff of smoke. There is no confirmation dialog and no setting to require one. The gesture is a normal drag, so it happens most often when you meant to do something else entirely — reordering, or just clicking imprecisely on a trackpad.
The second is quieter: reordering. The Dock interprets horizontal movement during a click as a request to move that icon. Because a click and a very short drag are nearly indistinguishable, your carefully arranged order drifts over weeks without any single moment where you notice it happening. Eventually the icon you reach for by muscle memory isn't where your hand expects it.
Both are the same design decision: the Dock is built for direct manipulation, and direct manipulation has no undo.
What Lock Dock Items does
With the lock on, your pinned set and its order are fixed. Dragging an icon out won't remove it. Dragging one sideways won't reorder it. Nothing can be added to the pinned layout either, so an installer that helpfully pins itself finds the door closed.
What doesn't change is everything you actually use the Dock for. Apps still launch on click. Right-click menus still open. Running apps still appear while they're running, and their indicator dots still work. You can still drop a file onto an icon to open it with that app, and the Recents, Files and Trash groups behave exactly as before.
Who this is for
It tends to matter most in three situations. On a trackpad, where small movements during clicks are unavoidable and accidental drags are frequent. On a shared or family Mac, where someone else's tidying becomes your missing app. And on managed machines, where a standard Dock layout is part of how the setup is meant to work.
Turning it on
- Arrange your Dock the way you want to keep it.
- Click the DockLockr lock icon in your menu bar.
- Switch on Lock Dock Items.
To rearrange later, toggle the lock off, make your changes, and toggle it back on. If accidental resizing is also a problem for you, pair this with Lock Dock Size, which makes the Dock's resize handle inert.