Corrupted display drivers frequently trigger D3D9 errors. A clean installation ensures legacy profiles are refreshed.
Third-party background overlay tools (like MSI Afterburner or RivaTuner) are crashing the fragile d3d9.dll environment. Step-by-Step Fixes for Ran Online D3D9 Error how to fix d3d9 application error ran online
Sometimes the error is caused by the way the application tries to open or by background software. Failed to Create d3d9 Device in Steam Fix [Solution] Corrupted display drivers frequently trigger D3D9 errors
Common D3D9 errors in Ran Online: