Resolved Dual Monitors with Sonoma 14.6.1 on M1 Max Studio

[inglesworth]

So I've just taken the plunge and updated my OS from Ventura to Sonoma on my M1 Max studio.
I have 2 monitors, which are both the same LG monitors. No hubs for video connectivity. One is plugged directly to the studio's HDMI port, the other is going from a USB-C port to HDMI cable.

The first time I booted into Sonoma, it worked just fine as an extended display. However, since that first boot, I can not seem to actually use my second monitor. It boots up and I can see the wallpaper on both monitors, but I can not drag the cursor or any windows fully onto the second screen. I can set it to mirror and it works just fine. I can also change the main monitor in the display settings and the top menu bar and cursor will move to the other screen and I can use it. But then I can't move my cursor back to the first monitor again after that. Also, if I try to drag the cursor over to the other screen for more than 5 second or so, the keyboard and mouse become unresponsive. Even unplugging them and plugging them back in doesn't work. I have no choice but to hold down the power button to force a shutdown and then restart the machine.

Any advice on how I might be able to get my second monitor to work correctly?

 

[MarkC426]

Do you have other ports on the monitor you could try i.e. DP or DVI….?

 

[inglesworth]

Do you have other ports on the monitor you could try i.e. DP or DVI….?

You know what... I've changed it to resolved. I discovered that the issue was with a kvm switch I was using. The switch wasn't designed for multiple displays, but I just wanted to be able to access a different computer on only one display sometimes. As it turns out, that also means that I can't move the mouse off of the main display for some reason. Thanks for responding, though.

 

[MarkC426]

FYI if your monitor has multiple ports, you can connect your other computer.
Then select the input on the osd of the monitor, and just have a kvm for kb and mouse.