How to lock the Dock on a shop or showroom Mac

A demo Mac has a job, and the Dock is part of it

On every other shared Mac the Dock drifting is an annoyance. On a machine that exists to sell something it is the pitch going wrong: the app you want people to try is not there, because somebody dragged it off three customers ago.

What actually happens on a display unit, in rough order of how often:

• Apps dragged out of the Dock. Curious hands, and the puff of smoke is fun. The app is still installed and now nobody can find it.
• The size changed. The divider sits in the busiest part of the screen. One brush and every icon is wrong.
• Random apps added. Whatever a customer opened stays in the Dock afterwards, so by Friday the Dock is a history of the week.
• Auto-hide switched on. Now the Dock is invisible and the next person thinks the machine is broken.

The keys, with the demo one first

defaults write com.apple.dock contents-immutable -bool true
defaults write com.apple.dock size-immutable -bool true
defaults write com.apple.dock position-immutable -bool true
defaults write com.apple.dock autohide-immutable -bool true
killall Dock

contents-immutable is listed first on purpose. On a personal Mac it is the one people skip. On a demo unit it is the whole point: it is what keeps the apps you chose in the Dock and keeps everything else out.

Each grays out the matching control in System Settings. They survive a restart and a macOS update. Every key with its type is in every Mac Dock defaults command.

Recent apps, which undoes the contents lock's whole purpose

macOS adds a section of recently used applications to the right of the Dock, and the contents lock does not remove it. So a locked Dock still grows a tail of everything customers opened.

defaults write com.apple.dock show-recents -bool false
killall Dock

On a display unit this is not optional. More on it in how to stop recent apps appearing in the Dock.

More than one machine: identical, not just stable

This is the part that has no equivalent on a home or office Mac. A bank of display units has to match each other, and they drift apart one small change at a time until a customer walks down the row and sees four different Docks.

So the order of operations matters more than the settings do:

1. Set up one machine exactly as every machine should be. Dock arranged, recent apps off, all four locks on.
2. Then capture the image or the configuration you clone from.
3. Roll it out.

Anything configured after the baseline is captured lives on exactly one machine and is undone the next time that machine restores. That is how a row of identical Macs stops being identical.

If the units restore to a known state overnight, the same rule applies with more force: the locks belong in the baseline, not in the running session, or you will be setting them again every morning.

Which mechanism suits a shop floor

• A defaults command. Free, one line to undo, and enough when the Terminal is not reachable by the public. It is per account, so it applies to the login the demo runs in.
• A configuration profile installed by hand. Holds through Terminal, through a restart, and through deleting whatever created it. It covers that login and is removed on purpose in System Settings, General, Device Management.
• A profile pushed by an MDM. The right answer for a chain, or for anywhere the units are already managed centrally. It is the only version that can be made genuinely unremovable and scoped to every account on the device.

All three compared, with what each costs: how to lock the Dock on a Mac, 3 ways compared.

The second screen, if the unit has one

Some display setups drive a second panel facing the aisle. The Dock is not assigned to a screen: it follows the pointer, and there is no defaults key and no System Settings switch that changes that. If a customer moves the mouse to the wrong edge, the Dock goes with it.

The workarounds and what each one costs are in how to keep the Mac Dock on one screen.

A sensible setup for a display unit

1. Put exactly the apps you are demonstrating in the Dock, and nothing else.
2. Turn off recent apps, so the Dock stops recording the week.
3. Lock contents first, then size, position and auto-hide.
4. Decide what happens on any customer-facing second screen.
5. Capture the image now, then clone.
6. Write down what you set, so the next person to touch the row knows why the settings are gray.

Common questions

Does the contents lock stop apps being installed?

No. It stops the Dock's icons being added, removed or rearranged. What can be installed or opened is a separate matter and belongs to Screen Time or your management tool.

Customers keep opening things. Does that change the Dock?

Only through the recent apps section, which is separate from the four locks. Turn it off and an opened app leaves nothing behind.

We restore the machines every night. Do we still need this?

Only if a full trading day of drift is acceptable, and it usually is not: the Dock is worst in the afternoon, when the most people have used it.

Is this the same as a front desk Mac?

Close, but a front desk is used by staff and only seen by customers, where a demo unit is used by customers directly. See a front desk or showroom Mac for the staff side, and a library or public Mac for machines with no commercial purpose. At home it is a family Mac.

Will a macOS update clear the locks?

No. They live in the account's preferences rather than in the system. A restore image will replace them with whatever the baseline holds, which is the reason to put them in the baseline.