How to lock the Dock on a Mac

The short version

macOS can lock the Dock. It just gives you no switch for it. The settings have been in macOS for over fifteen years, but they live in defaults write commands with no place in System Settings, which is why most people never find them.

There are four locks, and each one works on its own:

• Size, so brushing the divider stops resizing every icon.
• Position, so the Dock stays on the edge you chose.
• Contents, so icons cannot be dragged out or rearranged.
• Hide and show, so the auto-hide setting cannot be flipped.

The three ways to apply them follow, with what each one costs you.

The three ways

1. Terminal

Four commands, one per lock:

defaults write com.apple.dock size-immutable -bool true; killall Dock

The others are position-immutable, contents-immutable and autohide-immutable. The full guide covers all four, including the fifth one people repeat that does nothing.

Good when: it is your own Mac, you know what you want, and you will not need to change it often.

The catches. Each lock is a separate command with an exact key name, and a typo fails silently with no error. Changing your mind means going back to Terminal. Nothing records what your Dock looked like before, so if you lock it at the wrong size, you set the size again by hand. And System Settings goes gray with a message about a profile, which is confusing enough that people search for what went wrong months later.

2. A configuration profile

A profile is what organizations use to manage Macs. It sits above user preferences, so it holds when a preference would not.

Good when: other people use the Mac. A front desk, a classroom, a shop display, a shared family machine.

The catches. You have to write the profile XML or use something that generates it. macOS asks you to approve each one. And it is deliberately harder to remove. It outlives the app that installed it, so you must remove it on purpose in System Settings, General, Device Management.

3. An app

An app sets the same macOS settings, with switches.

Good when: you want to see what is locked, change it without looking anything up, and get your original setup back.

The catches. It costs money, and it is another thing running. What you get for that is visibility and reversibility: which locks are on, one click to change them, and a snapshot of the Dock you had before you locked it.

Still Dock, the app that locks your Mac's Dock, is ours, and it is the app-shaped way to lock the Mac Dock. It does the four locks, adds a display pin and a Cmd Q guard that Terminal cannot do at all, and can install the profiles from point 2 without you writing XML.

Which one to pick

• Your own Mac, set once, comfortable in Terminal. Use Terminal. Genuinely, it is free and it works. Write down what you ran.
• Your own Mac, you expect to adjust it. An app, because the retyping is what wears people down.
• A Mac other people use. A profile. Nothing else survives contact.
• A managed fleet. Your MDM, centrally. Do not do this machine by machine.

Using more than one screen? The Dock also jumps between them, which is a separate problem with its own fixes: how to keep the Mac Dock on one screen.

Common questions

Can you lock the Dock on a Mac at all?

Yes. The settings exist in macOS and have for years. System Settings has no switch for them, so locking the Dock looks impossible. All three methods on this page set the same underlying settings.

Does locking the Dock stop me adding or removing apps?

Only if you lock the contents. The size, position and hide locks leave you free to rearrange the Dock as usual. Lock only what you want held.

Will it survive a restart?

Yes, all three ways. These are stored settings.

Can I lock the Dock without paying?

Yes. The Terminal route is free and it works, and our command generator writes the commands for you. You are paying for a switch, a label saying what is on, and a record of the Dock you had before.

Why has System Settings gone gray?

The lock is working. macOS disables the control and says it is managed by a profile. The wording confuses people months later when they have forgotten they set the lock. See Mac Dock settings grayed out.

Do these conflict if I use more than one?

A profile wins over a Terminal setting. If your settings are grayed out and undoing the commands changes nothing, look for a profile.

Is the app doing anything Terminal cannot?

For the four locks, no, and we say so on the home page. Pinning the Dock to one display and guarding Cmd Q are different mechanisms with no Terminal equivalent.

Will any of this survive a macOS update?

The preferences and profiles normally carry across. Apple can change Dock behavior in any release, which is true of all three approaches equally.

What is the free way to try before deciding?

Run the size command. If freezing the size fixes your problem you may need nothing else. If you find yourself undoing and redoing it, that is your answer.

If you want the full list of keys as well as the locks, see every Mac Dock defaults command. For the multi-monitor problem specifically, DockLock and Still Dock compared covers the apps that solve it, LockMyDock included.