Since vCenter Orchestrator 4.1 PostgreSQL is not listed in the vCO configuration database tab drop down databases list.

To enable it back:

  • Edit vmo.properties in C:\Program Files\VMware\Orchestrator\app-server\server\vmo\conf
  • Add this line: ch.dunes.config.enable-unsupported-db-providers=true

Please note that this is an unsupported configuration - Do not do this on production servers !