The error is essentially a "missing file" or "blocked file" error. In 90% of cases, it is resolved by simply running the software as an administrator or by performing a clean re-installation with antivirus software disabled.

Ensure you have ample free space on your hard drive (preferably an SSD). If you installed on an external hard drive, move the installation to your internal C: drive. 5. Clear Temporary Files Corrupted temp files can interfere with new installations. Press Windows Key + R . Type %temp% and press Enter.

Go to File > Open and navigate to: C:\Windows\System32\drivers\etc

Known issue where Windows updates (like v2004) introduce a version of onnxruntime.dll that conflicts with the one in Lumion’s folder.

If you find any, delete those lines, save the file, and restart Lumion. 6. The "Nuclear" Option: Clean Reinstall

Avoid installing Lumion on external drives or custom network folders if possible. Keep it on the primary C:\ drive.

Windows Defender or third-party security software blocked the plug-in from reading the local installation folders or opening a local communication port. Step-by-Step Troubleshooting Methods