If your monitor isn't displaying correctly with your KVM switch, it's likely a refresh rate or resolution issue. These problems often arise from using low-quality adapters or when the monitor's HDMI ports are limited. Thankfully, these issues are usually easy to fix. I mostly use the Linux machine. When I run "Preferences->Display", the "Resolution" choices range from 1920x1200 down to 800x600. If I use the to KVM switch to switch from the Linux machine to the Windows machine, I get a. You shall try setting a lower resolution output (such as 720p or 1080p) and then reconnecting to the KVM switch to test if the monitor displays an image. Check the KVM switch's specifications and adjust. It means that the video signal being output exceeds the recommended resolution and refresh rate.