Have a bit of a weird issue. I suspect the problem is with my audio interface though.
Using Win 10, Echo Audiofire 2 using the 5.7.6 driver (found the 5.8 would randomly reassign outputs), i5 750/8gb ram.
I can get sound fine through Sonar, also Notion, and through iTunes and MediaMonkey and also through Chrome and Edge on YouTube or iPLayer.
So despite a few funky things with the Echo device (have to often connect/reconnect etc) it is mostly working OK.
However I cannot get any standalone instruments like Kontakt to work. I have tried Kontakt 5, Rap Pro, EWQL Symphonic and UVI Workstation and none of them will produce sound, although the output meters in the actual apps are working. I have checked settings, everything appears correctly routed. the programmes are getting MIDI from my keyboard and outputting sound from their outputs but nothing is appearing at the soundcard mixer.
yet these all work fine inserted as soft synths in Sonar (Pro JP)
any ideas other than buying a newer interface?

mgh
Have a bit of a weird issue. I suspect the problem is with my audio interface though.
Using Win 10, Echo Audiofire 2 using the 5.7.6 driver (found the 5.8 would randomly reassign outputs), i5 750/8gb ram.
I can get sound fine through Sonar, also Notion, and through iTunes and MediaMonkey and also through Chrome and Edge on YouTube or iPLayer.
So despite a few funky things with the Echo device (have to often connect/reconnect etc) it is mostly working OK.
However I cannot get any standalone instruments like Kontakt to work. I have tried Kontakt 5, Rap Pro, EWQL Symphonic and UVI Workstation and none of them will produce sound, although the output meters in the actual apps are working. I have checked settings, everything appears correctly routed. the programmes are getting MIDI from my keyboard and outputting sound from their outputs but nothing is appearing at the soundcard mixer.
yet these all work fine inserted as soft synths in Sonar (Pro JP)
any ideas other than buying a newer interface?

Since you have uninstalled a reinstalled and played with the drivers, you will probably have to 
go back into set up and "reset" them...

You will need to allocate your audio drivers inside the standalone application.

Thanks guys. Have already checked the audio settings which are correct.
As I say within the instruments things are working I can see keys responding to the midi from my controller and the output meters are active when notes are sounding. ..
It's either the audio driver or some setting in Windows I think. Will keep digging