Hi,

I've just installed the Dell P3421W with a desktop PC on the HDMI port and either my 2017 MacBook Pro (with macOS Monterey) or my new ThinkPad T14 on the USB Type-C port.

Both laptops seem to charge OK and the 4K native video also works OK and looks good for what I need.

The built-in Dell P3421W KVM has my Corsair keyboard and SteelSeries mouse on the inputs. Switching the video input also switches the input devices.

Although there are no issues with the ThinkPad T14 (and the same for my desktop PC), there is an issue with the MacBook Pro where the keyboard and mouse become unusable immediately or soon after changing to them.

The lights stay lit on the keyboard but they do off on the mouse.

I attempted to install the Dell DDM on the MacBook Pro but it's probably not supported anyway. However, it shouldn't be needed to switch USB inputs as I've configured the monitor to do this.

Please does anyone have any ideas about how to fix this ?

Thanks