Because DLL files execute code directly in the system memory, overzealous antivirus software (including Windows Defender) sometimes flags Lumion DLLs as heuristic threats. The antivirus will then quarantine or delete the file without warning you. 3. Outdated or Conflicting Graphics Drivers

: Many Lumion DLLs rely on Microsoft Visual C++ Redistributable packages. Reinstalling the latest versions can resolve underlying dependency issues.

Open your antivirus software history/logs. If you see that a file inside the Lumion directory was recently blocked or removed, restore the file and add an exception for the Lumion folder.

Navigate to the Redist folder within your Lumion installation directory. Run VC_redist.x64.exe and select .

Check for any blocked Lumion files and select Restore .