Occasionally when I plug in an external screen, my mac somehow won't let me move my mouse/trackpad to some parts of my display. Here's what's going on with my machine right now:

How Screens are Placed

How Screens are functioning

I should note:

  • MacOS 11.6; 15 inch 2019; 2.3 GH 8 core Intel i9
  • It doesn't happen all the time - sometimes external displays works fine.
  • It happens using both HDMI and DisplayPort cables.
  • And when it happens the inaccessible zones aren't always the same - it depends on the arrangement of the displays in System Preferences.
  • Repositioning my external displays or detaching and reattaching them doesn't help - when the screen refreshes after repositioning or reattaching them, the inaccessible zones remain, or shift.
  • The only thing that seems to resolve the issue is restarting my machine (which I can't always do when I'm in the middle of something so isn't an ideal solution)
  • while posting this the inaccessible zones actually increased in size (to the right)! I wasn't even able to use my mouse to move my cursor properly while trying to edit and update this - i had to use my arrow keys to move my cursor around. So strange.
  • This machine has always been a little buggy (e.g.: it randomly does a full-screen zoom in on occasion without me hitting the modifier key to invoke that function). Not sure if this is related.

I've looked around and haven't seen anyone else reporting this issue. Is it just me or can anyone explain what is going on and how I can fix it without needing to restart my machine?

  • I wonder if this is going to come down to resetting NVRAM and SMC apple.stackexchange.com/a/345810/205221
    – Mugshep
    Commented Nov 22, 2021 at 11:43
  • this seems kind of similar to apple.stackexchange.com/q/35686/205221, although my cursor doesn't jump over the part that's not accessible.
    – Mugshep
    Commented Nov 23, 2021 at 12:04
  • I've since had numerous problems with this machine, and I was told by a service technician that this sounded related to issues I'm having with my motherboard. He recommended replacing the whole board to address them. Have not done that yet but noting here in case that's of help to anyone.
    – Mugshep
    Commented Jul 7, 2022 at 12:14

1 Answer 1


I suppose your only option for clearing up the processes responsible for this ( avoiding the restart which you said you want to avoid) would be to log out of the graphical session (apple menu log out) and then try logging back in.

Long term, Apple would have to fix this with a patch - you should be able to get to those portions of the screen always - just not transition out of the screen to any other place since there's no directly connected screen space contiguous with the areas you have configured in your curious (to me) layout.

Shutting down the OS is my first option when displays are messed up. You get a gentle reset by disconnect / reconnect and if you say that doesn't cure this glitch. No need for SMC / NVRAM in my experience but I can’t reproduce this on my setup - I don’t have the same GPU / hardware and macOS version you do.

Full start of the OS ensures the buffers where the OS stores display information is cleanly wiped, not corrupted, and then the display detection can run on a clean setup.

Has Apple fixed this in any updates or upgrades for you?

  • I can confirm this worked, but wish I understood what is causing the issue though!
    – Mugshep
    Commented Nov 24, 2021 at 12:54
  • I've had the problem several times since posting, and although this has worked most of the time, logging out didn't resolve the issue for me once today. It required a full restart. Strange.
    – Mugshep
    Commented Dec 1, 2021 at 12:38
  • I've edited the answer - some typos. I expect a full restart to fix this sort of corruption / bug @Mugshep
    – bmike
    Commented Apr 18, 2023 at 14:18
  • I hadn’t accepted as answer bc I it seemed like more of a work-around, but this is the only method I’ve come across to address so I have accepted as answer. Thanks for the info (and follow-up)!
    – Mugshep
    Commented Apr 20, 2023 at 5:07
  • Regarding your question of whether Apple has addressed, I haven’t come across this in some time, but I’m no longer using the same screen set up where I am placing two additional screens that are only partially contiguous both vertically and horizontally. If I encounter again I will post here.
    – Mugshep
    Commented Apr 20, 2023 at 5:10

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