262

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.

  • 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. – Melvin Jefferson Dec 29 '17 at 21:10
  • 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. – Eric Leschinski Jul 26 at 18:22
434

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.

  • 3
    Cool. I didn't know, every time it moved I will change it with System Preferences -> Display -> Arrangement. – Fernando Gonzalez Sanchez Mar 22 at 15:59
  • 3
    WOW I am so glad I finally found this lol. I could never figure out the trick. I would move to the bottom, click, move up and down, and sometimes it would appear lol – quemeful Apr 10 at 15:10
  • 5
    +1. Any way to disable this option? I'm using two external monitor plus the laptop one. The arrangement is the two external side-by-side and the corners where they touch is arranged at the center-top of the laptop screen. Because of this there is a no-transition half-bottom edge on each of the external screens that I eventually bump into when moving the mouse down to the laptop screen. Really annoying. Working on Mojave. – L. Holanda Jun 24 at 22:56
  • that does not always work easily that way. Now and then, Dock vanishes from my main screen. And I found myself fighting with movements and clicking to focusing window/screen for several seconds, disrupting my workflow. – Andre Figueiredo Aug 27 at 20:17
28

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.

22

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.

  • 3
    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. – prototypical Apr 17 '16 at 15:08
  • 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 at 17:46
20

(I wanted to add this comment to @Mr Rabbit's answer, but I can't as I don't have the requisite 50 points, so adding it here:)

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.

I don't see how anyone would find these motions to be intuitive. How about a simple right-click option to "move Dock to this monitor"?

  • 3
    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. – Geradlus_RU Jan 10 '16 at 5:18
  • @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 at 17:48
18

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.

6

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.

1

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.

  • 2
    This looks like it should work, but unfortunately it doesn't. – Jason Sims May 7 at 21:24
  • 3
    nope, doesn’t work on mojave. – georgexsh May 8 at 4:06

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