Uninstall Lumion → delete remaining folders ( C:\Program Files\Lumion , %APPDATA%\Lumion ) → reinstall latest version.
From digging through forums and support tickets, here’s what solves it 90% of the time: Uninstall Lumion → delete remaining folders ( C:\Program
Once you have Lumion working again, follow these best practices to prevent "Channel not found" from returning. Uninstall Lumion → delete remaining folders ( C:\Program

This will close in 0 seconds