Cannot move the dock from iPad to main monitor when using screen mirroring

This issue happens because macOS doesn't allow the Dock to move to a display whose bottom edge is perfectly aligned or overlapped with another screen. In System Settings → Displays → Arrange Displays, drag your screens so the one you want the Dock on isn't exactly flush with the one next to it - leave a few pixels of offset at the bottom. That small gap is enough for macOS to recognize it as a valid Dock location. The red circles in the screenshot show overlapping layouts that won't work, while the blue one shows the correct setup. Also make sure that "Displays have separate Spaces" is turned on in System Settings → Desktop & Dock. If your extended screen is positioned above another, the Dock can't move there either - it only appears on displays that touch the bottom edge of your layout.

[Edited by Moderator]

Thank you for the screenshots. Yes, they came out dark be clear enough for us to see.

I did a quick test, and arranging the displays as in the image below (the second display is using Airplay to a second, but whether a Mac, iPad or a directly attached display should make no difference).

I set the Dock at the bottom and made it visible (mine is always on one side and hidden).

The Dock went to the lower display (that would correspond to the iPad in your setup), as expected.

By "pressing against" the edge of the display as shown below, the Dock DID move to the topmost display.

I have done this before with an iPad as well in previous versions (but don't have one available at the moment to do that test).

The decisive factor is to bump the cursor against the bottom edge, on either side. If you put your cursor at the seam between two displays it just moves to one or the other.

In your case, pressing the cursor against any of the green areas should bring up the Dock to where you want.

Does your display arrangement match what JulyIGHOR showed? Then his answer explains it.

If not - as if, for example, you have the iPad display set beside the Mac one, and the Dock is set to the bottom, then just move your cursor to the Mac display and move it against the bottom edge; the Dock should move there.

Also: if the Dock is set to be on one side (either left or righ), it will be on whichever display is set to be on that side - so as to be on the edge of the combined displays.

I would try the DockLock Lite app from the Mac App Store. It is able to relocate the Dock to a selected screen. Try to use that app and in the menu select the Display you want the Dock visible, and deselect the other Display. After that, does the Dock relocate to the right screen?

Do please post the screenshot that JulyIGHOR requested.

As a little additional note: if you’re to move the Dock you need to “bump into” a part of your mac screen that is an edge of your combined screen - see the one marked BLUE in JulyIGHOR’s post.

I personally find it odd to have the Dock effectively in the middle of stuff, but it should work, and I have tested this and it does.

I don’t think that’s the expected behavior with macOS.

Could you please share a screenshot of the Display Arrangements when the iPad is positioned below the main screen and with the offset you tried?