Problem Audio connection


I want to report a Problem about Audio Connection (F4), that appeared on Cubase Ver 9.5 till now.
I am sorry I can not explain every step to let it happen, because almost of time, it just suddenly happen.
The problem is, my 1st audio output buss, which is the default Out, suddenly disappears.
It happens when I add more Output buss to work with summing interface, and change the Output setup for some of my audio tracks.
In this case is 4 more Output connection.
I tried to quit the project and re-open it, what happen is, the Stereo out (1st default Output) appear again, but without Audio device (showing “Not connected”)
And, I can not do anything on it, even expanding, or choose an Audio device or Output.

In the photo attached is what shown on my screen.

It happened after about 30minutes working on the project. And it should happen with all of the projects if I try to work continuously.

I hope Steinberg Supporters can help configure the problem and get it fixed.

My system is:

  • Mac Pro Tower 2008 with 24GB of DDR2 Ram.
  • OSX 10.11.
  • Cubase Pro 10.
  • RME Fireface 800 audio interface.

Thank you.

And Good luck everybody.


As I can see, the Analog 1 and Analog 2 is used for the Stereo Out 1 bus. Which is more over the “Main Mix” bus (with the orange speaker). So the question is, how did you add this bus, and if it was by purpose?

You can use the Device Ports exclusively only. You cannot use the same Device Port for multiple Buses.

Hi Martin,

I used the same audio Output for multiple Vst Connection many time and I use it very often, you can try and you should see it works.

However in this case, I was trying to create another Buss to replace the “Un-touchable” Stereo Out, to work on summing, If I don’t do it, I can not use 2 of my output for summing. It wasn’t there before the problem.

You should try using the same device port for multiple busses, I bet it works even for input or output. I tried this since Cubase 7 or 8 without problem.
My photos attached showing below :

Thank you for your reply.


Ah even in the old screen capture, Stereo 5 also has the same device with Stereo 1, no any problem till now.

Just the Stereo Out (default) disappeared while working. And it came back showing “Not connect” and Un-touchable after I re-open the project.

Thank you.

Sorry, I was wrong.

The exclusivity works only for Monitor Channels (Control Room) if you enable this in the Preferences > VST > Control Room. All other Device Ports are not exclusive.

Thank you Martin,

I used the second Out to record some Vsti directly while playing, reasonable I am a Piano player and I don’t record Midi for almost of my Vsti tracks.
Sure we can use a group channel this case, however it isn’t the point of this problem, It happened even when I make everything normally.

I know it’s hard, so I tried in 6 months to figure out how can it happens, but no hope.

I think not much people use multiple Output connections so this problem may rarely happen.

Hi Martin,

Any hope with this issue?
I think the problem is there when we work with at least 2 Output buss with the same routing.
Or we try to change the track routing many time.
It happens very often to me since Cubase 9.5

Thank you and wish you all a Happy New Year.


I’m not really an expert in this area, but there are some facts I know (maybe you will get an idea):

  • The Audio Connections > Outputs settings is stored with the project. So you should be able to have a different settings for different projects.
  • The Audio Connections > Control Room settings is stored globally. So once you change it in one project, the change affects all projects.
  • The Control Room has a higher priority over Outputs. First the Control Room connection is loaded, then Outputs.
  • If Cubase can find the Device Port, which has been used (as far as I know, this is based on a string - Device Port name, so if you somehow achieve to rename the Device Port, it will not be recognised; but I’m not 100% sure about this), Cubase connects it.
  • If Cubase doesn’t find the very same Device Port which has been stored, there is a mechanism to connect at least something. So Cubase is searching for an unused (Not Connected) Device Port, and connects it.

Be aware of these preferences:

  • VST > Do Not Connect Input/Output Busses When Loading External Projects: disabled by default.
  • VST > Control Room > Exclusive Device Ports for Monitor Channels: enabled by default.

Any idea?