Viewer fails to start – error messages

Whenever  Cortona3D Viewer fails to start with or without an error message it is recommended to follow these steps:

  • Uninstall Cortona3D Viewer
  • Go to
    • For 32-bit OS – “C:\Program Files\Common files\Parallelgraphics\Cortona” and clean the installation folders
    • For 64-bit OS – “C:\Program Files (x86)\Common Files\ParallelGraphics\Cortona” and clean the installation folders
  • Install Cortona3D Viewer
    • The latest version of Cortona3D Viewer can be found here

If the issue still persists, try to register shelley3.dll:

  • Open Run
  • Copy this: regsvr32 "C:\Program Files\Common Files\Parallelgraphics\Cortona\shelley3.dll"
  • Click OK