When I connect my external monitor via USB-C the system behaves as if there is a "down click" condition on the track pad. I do not have an external mouse connected. If I unplug the monitor, the problem goes away. Restarting the computer does not solve the problem.
MacBook Pro
The Mac uses an "all ports active" method for reading mouse movements, clicks, and typing. With two keyboards connected, you could literally type every-other key from every other keyboard. With two mice connected, moving either mouse moves the system pointer, and clicking either clicker cause a system click.
Your description sounds to me like your USB-connected display thinks it has a mouse connected, and it thinks the clicker is activated.
I suggest the thing that needs to be reset is your display.
For the Apple Studio Display, for example, it requires a substantial timeout. Disconnect from power and data for a quarter hour. (Sitting facing the corner or sitting on the stairs is optional.)
The Mac uses an "all ports active" method for reading mouse movements, clicks, and typing. With two keyboards connected, you could literally type every-other key from every other keyboard. With two mice connected, moving either mouse moves the system pointer, and clicking either clicker cause a system click.
Your description sounds to me like your USB-connected display thinks it has a mouse connected, and it thinks the clicker is activated.
I suggest the thing that needs to be reset is your display.
For the Apple Studio Display, for example, it requires a substantial timeout. Disconnect from power and data for a quarter hour. (Sitting facing the corner or sitting on the stairs is optional.)
The monitor has a USB hub built in. I disconnected all usb devices from the monitor and the problem went away.
Hi there a_bluebike,
Thank you for posting to Apple Support Communities.
Try testing the issue in safe mode. This will start up your Mac so that it performs certain checks and prevents some software from automatically loading or opening, which could help narrow down the cause of the issue. This article will walk you through the steps: Start up your Mac in safe mode - Apple Support
Apple silicon
1. Shut down your Mac.
2. Turn on your Mac and continue to press and hold the power button until you see the startup options window.
3. Select your startup disk, then press and hold the Shift key while clicking “Continue in Safe Mode.”
4. Log in to your Mac. You might be asked to log in again.
Intel processor
1. Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.
2. Release the key when you see the login window, then log in to your Mac.
3. You might be asked to log in again. On either the first or second login window, you should see ”Safe Boot” in the upper-right corner of the window.
Then, restart as normal to test if the issue continues.
If it does, are you able to customize the controls so the trackpad works as you'd like by changing its' settings? Learn how to do this: Change Trackpad settings on Mac - Apple Support
That should help. Let us know how it goes.
Take care.
Macbook Pro 14-inch, 2021 - trackpad click problem with monitor connected
