After completing a project that plays back just fine I attempt to export an audio file. It goes thru the real time record just fine, but when I attempt to play the file there is no sound. I opened the file in Sound Forge and it has no signal showing. I am using a Yamaha MOXF6 for recording and playback. Everything works fine except the exporting to an audio file. This has just begun after having done this successfully before. However, even the successful exports had low volume requiring me to boost the volume in Sound Forge.
I expect you send the MIDI data to MOX6, right? So MOX6 is the sound generator. In this case, make sure, the sound is recorded to Cubase (as an Audio) vi Line Out (from MOX6) to Line In (of your Audio Device).