I'm using Openstudio 1.8.5, when choosing ddy file that has been generated by internal E+ tool (installed with OS 1.8.5) from folder: C:\Program Files\OpenStudio 1.8.5\share\openstudio\EnergyPlusV8-3-0/preprocess/weatherconverter/weather.exe
Openstudio show error below (image), epw souce file was generated by meteonorm.