Good news first - I got dspMixFx to work under MacOS High Sierra 10.13.
I’m not sure if it was the latest update by Apple. At the same time I reinstalled all of the drivers and suddenly everything worked.
I worked a few hours in different projects and all seems running fine, so far.
Steps I did:
- Updated to the latest version of MacOS
- Reinstalled all of the drivers (including the latest USB-Driver from the Yamaha-Homepage)