By following this guide—deleting the config, repairing VC++ runtimes, and performing a clean install with antivirus exclusions—you will restore rendering 99% of the time.
But if you lose HQ functionality, revert to Part 4 above. The "Lumion Channel not found in installation" error is terrifying because it sounds like your software is irreparably broken. In reality, it is just a map-reading problem: Lumion has the map (your GPU), but lost the legend (the channel files). By following this guide—deleting the config
Lumion channel not found, skipping load routine, high quality rendering, Lumion error fix, render channels missing, GPU detection Lumion, high quality shadows not working. repairing VC++ runtimes