I have a larger, external monitor connected to my MacBook Pro and have arranged it such that the dock is in the external monitor (via System Preferences > Displays > Arrangement, by dragging the white bar to the larger screen). This works fine, except for the fact that every now and then, the dock will suddenly shift back to my MacBook screen, but when I open up Displays to change this back, the white bar is still on the external monitor. So I have to drag it to the smaller screen, and then drag it back to the external monitor.

It's a minor issue, obviously, but I've noticed that it has been happening more and more frequently and it's getting quite annoying. Perhaps there's something I've been doing unintentionally for this to happen?

I'm using Mavericks, 10.9.5.

  • 1
    This is a glitch in MacOS that has existed for quite a while. I would contact Apple and see if they can add a "lock dock" command in the Dock Preferences. Dec 29 '17 at 21:10
  • 4
    There are 2 ways to accidentally move the dock to the other desktop. Either because one monitor activates/deactivates and so the dock transports itself to what it perceives as the only remaining screen. Second, the overhang area on your vertically stacked monitors has different width/height; it catches your cursor, thus summoning the dock to that screen. To move it back, put focus on desktop. Find the overhang area from one monitor to the other. Place your cursor on that overhang and scroll down, the cursor should remain in place as you move. The dock should transport itself to that monitor. Jul 26 '19 at 18:22
  • 1
    @EricLeschinski, thanks for the input. Mr Rabbit has a more thorough explanation: "You can summon the Dock on a different display by moving the cursor to the bottom of the desired display" :-) Please, upvote that. Aug 23 at 5:13

You can summon the Dock on a different display by moving the cursor to the bottom of the desired display, and then continuing moving down. It may be possible that this is occurring when you inadvertently perform that action.

I answered a similar question: cmd-tab behavior on Mavericks with multiple displays.

  • 2
    This still works on macos Big Sur 11.4 But it's so flakey for me. I click on the screen I want it to appear on and then I literally need to move my cursor up and down in the bottom spot, and move to different areas at the bottom of screen before it suddenly works. Ridiculous! May 28 at 15:45
  • This does not work if position on screen is set to Left (also moving mouse to the left as it works when position set to Bottom does not work). My primary screen is on my mac, but Dock is on one of the external screens if position is set to left. I would expect the Position to apply to the primary screen, not to the arrangement of the multiple screens.
    – trainoasis
    Aug 6 at 7:45

If you can't drag the mouse down due to stacked monitors, or due to some other resolution differences between monitors. Go to System Preferences → Dock → Position on screen → click Left, and the dock will move back to the primary monitor.

Then you can go to the Bottom screen and follow the steps to summon the Dock, and it will return there.


Apple didn't account for the over/under monitor configuration, the overhang catches your cursor and summons the dock. In this case, the switching is constant and annoying.

One workaround is to put the dock on the side of the monitor, which will prevent the summon when the overlap catches your cursor.

  • 5
    I can't stand it either, but this issue has annoyed me to the point of accepting one annoyance to escape the other. It's even more annoying because it seems the solution of having the dock always present on the screen the mouse pointer is on is a simple and logical design. Apr 17 '16 at 15:08
  • 2
    I actually figured out a way to get this to work with under/over config. For the bottom monitor you can just move the cursor down to the bottom of the screen (and move the cursor up and down) as prescribed above. For the top monitor, if you move your cursor to the right corner you can't go 'down' to the bottom monitor. So you can move the cursor up and down there and run it into the bottom of the screen and the dock will move up to the upper monitor! :)
    – trebek1
    May 13 '19 at 17:46

The action that summons the dock to the opposite monitor is not very intuitive for me. This is what worked for me.

  1. Don't hold the mouse button down. (When people say "drag" the mouse, that usually implies with the mouse button held down.)

  2. The target area of the cursor needs to be at the bottom area of the monitor which doesn't currently have the dock at a place where the cursor can't move further down, i.e. this doesn't work on vertically stacked monitors along the area where the cursor can cross between screens.

  3. Once the cursor is "blocked", pause a sec, then continue the motion downward. The dock will be "summoned" to this monitor from the other monitor. This works for vertically stacked monitors as long as there is some place where the cursor is "blocked". If not, the cursor will just move to the other monitor since it is not "blocked". If you have identical resolution monitors, this will probably not work per @Geraldus_US's comment below. In that case you probably need to either left dock or right dock per @Geraldus_US. Alternatively, unplug the auxiliary monitor and the dock will switch to the main monitor.

  • 5
    I want to mention, that if you have vertical alignment where active monitor is above secondary the case than you have to move dock to left or right side to make it appear on primary monitor, otherwise it will always appear on bottom monitor. However, if your primary display is located below secondary dock appears at bottom automatically. Looks like misfeature, or requires additional tweaks. Jan 10 '16 at 5:18
  • 1
    @Geradlus_RU My monitors are vertically stacked with primary on the bottom, and the Dock on the bottom. But sometimes the Dock moves to the bottom of the top monitor which is weird. I’m sure it’s not supposed to do that but it happens.
    – Nate
    May 29 '19 at 17:48

In Mac OS, the Dock shifts to that monitor where you made a downward gesture at the bottom (or where the dock is usually positioned). That is, if you moved your mouse pointer further in that direction (as if going out of screen), it's an indication that you are looking for the dock. So Mac brings the dock there!

Look at the diagram below (yellow block is your monitor):

Mouse movement at bottom of screen

When cursor is blocked at bottom, moving the pointer further down brings the dock on that monitor. Can't use the words scrolling or dragging as you don't need to click/hold or use 2 fingers. It's just a normal mouse move.

So the cause: Probably you are someone like me who likes to leave the cursor at the bottom of the screen on one monitor while watching movie or keyboard-only coding/development, and then accidentally swipes/moves down the mouse/trackpad. Happens with me all the time.

Update: I just noticed that on the trackpad, it's not just a quick swipe.
You have to swipe-down and hold on the track pad. It does nothing when you lift your finger quickly like a normal swipe gesture.


To prevent this from happening type the following in Terminal:

defaults write com.apple.Dock position-immutable -bool yes; killall Dock

The Dock will stop moving.

The above domain and key was removed by Apple:

Apple has removed this position-immutable key from the defaults configuration because it was producing high call-volumes at IT helpdesk. Users would disable themselves by locking their Dock onto a phantom unreachable monitor. So now this command has no effect. You can verify this with command: defaults read | grep "Dock" which will report no such such key. Read more with man defaults and defaults -help.

  • 4
    This looks like it should work, but unfortunately it doesn't.
    – Jason Sims
    May 7 '19 at 21:24
  • 8
    nope, doesn’t work on mojave.
    – georgexsh
    May 8 '19 at 4:06
  • 2
    Bummer -- that's a very annoying behavior.
    – Camden S.
    Feb 18 '20 at 18:19
  • 2
    Funny how they could disable the workaround so quickly but couldn't just enable the behavior that people wanted in the first place.
    – Windmill
    Sep 11 '20 at 17:11
  • 1
    "Users would disable themselves by locking their Dock onto a phantom unreachable monitor" - I can't understand why no one in Apple thought about simple option "Show Dock only on main display". Mar 17 at 14:02

I also found this 'feature' annoying as you expect the Dock to be on one screen then you accidentally move the mouse to the bottom of the second screen and the Dock moves across. The easiest way to get it back is to move the mouse to the bottom of the screen you want the dock on. Sometimes you have to move it up then back down to get it to move.

Personally I found two options that helped me with this:

  1. At work I have my external monitor on a stand that sits behind my MacBook and arrange the screens so that the external monitor is just higher than my Macbook Screen then in the settings move the screen layout so they sit on top of each other. In this layout only one screen has a bottom as the external monitor is an extension to the Macbook Screen, thus stopping the Dock from moving. This layout also saves on desk space if you have a narrow desk.

  2. At home I use a monitor side by side but set the dock to auto hide, then when I need to get to the Dock I just scroll down to the bottom of whatever screen my mouse is on to get the Dock. Because the Dock is always hidden and comes on when I want it I don't seem to find it annoying like I do when it is fixed at the bottom of one screen.

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