How to stop your Mac’s display arrangement resetting

Why a Mac forgets where your displays go

macOS doesn’t remember an arrangement for “the monitor on the left”. It remembers one for the displays it recognises, from what each monitor tells the Mac about itself when it connects — its maker, its model and, if it has one, its serial number. When it sees the same displays again, it puts them back where they were. When it isn’t sure it’s looking at the same displays, it guesses, and the guess is what you see when the pointer leaves the wrong side of the screen.

Two identical monitors are the most common cause. If both report the same details, or one reports no serial number at all, macOS has nothing to tell them apart by. Your arrangement is still saved, but after a reconnect it can put the left monitor’s settings on the right one, so the two seem to swap places.

Docks, hubs and adapters are the second. Everything plugged into a dock reconnects at once when the Mac wakes or you plug the cable back in, and the displays don’t always arrive in the same order or on the same connection. Some docks use DisplayLink, which drives the display through its own software rather than directly, so how those displays are seen depends on that software too.

Sleep is the third. Many monitors switch themselves off properly when the Mac sleeps, so to the Mac they’ve been unplugged. When it wakes, each one arrives again as if new, and the matching starts over.

A different combination of displays — the office monitors one day, one screen at home the next — is a different arrangement as far as macOS is concerned. That one isn’t a fault: going back to the office should bring back the office layout. It’s when the same desk comes back wrong that something has gone missing.

What to try in macOS first

Set it again, carefully. Open System Settings → Displays, click Arrange and drag each display to where it actually sits, lining up the edges you move the pointer across. Then set the main display, and click Done. If you only rearranged by eye before, getting the edges right makes the pointer cross where you expect.

Use the same ports every time. With two identical monitors, keep each one’s cable in the same port on the Mac or the dock. If macOS tells them apart by where they’re connected, swapping cables swaps the screens.

Look at the monitor’s own settings. Some monitors have an automatic input search or a deep power-saving mode that makes them disappear from the Mac while it sleeps. If yours has one, turning it off can stop the monitor arriving as a new display at every wake. The names differ by maker; the monitor’s on-screen menu or manual has them.

Keep the dock’s software up to date. If your dock or adapter needs a driver or a DisplayLink app, an old version can be the reason displays reconnect in a different order. Update macOS too, through System Settings → General → Software Update.

None of these locks the arrangement. They make it more likely macOS recognises your displays, and if the arrangement still resets after sleep or a reconnect, you’re left setting it by hand each time.

What the fix does, and what it doesn’t

Keep display arrangement does one job: when macOS forgets where your displays go after sleep or reconnecting, MacFixes puts them back where you arranged them. It’s a free fix, and it doesn’t ask for any macOS permission.

It’s about position — where each display sits next to the others. If what keeps changing is a display’s resolution or refresh rate, that’s a different setting, made per display in System Settings → Displays. And if a display doesn’t show up on the Mac at all, it’s not an arrangement problem: check the cable, the port and the monitor’s input first.

Other things a multi-monitor Mac doesn’t do

The brightness keys only change a MacBook’s own screen and Apple displays — change an external monitor’s brightness from the menu bar instead. If your windows end up piled on one display after it reconnects, save a window layout and put them all back with one shortcut. And sleep causes another familiar problem: headphones that connect to a Mac nobody is using — turn Bluetooth off when the Mac sleeps.

Permissions, and turning it off

More fixes macOS doesn’t give you

One of 47 fixes and 10 apps in MacFixes. Every fix · Every app · Something else your Mac won’t do? Request it.