Hi. I have just bought a midas mr18 mixer. When i use cubase I got sound and everything is how its supposed to be. But then i want to listen to a song on spotify or watch a youtube film or a videofile from my pc, and there is no sound. I get sound from my pc when im switch to my pcs built in speakers, but none of my midas mr18 sources (soundcard menu in windows) provides sound. Thank you for all answeres in advance 
Quoting from manual page 26:
Using Several Audio Applications Simultaneously
You can allow other applications to play back via your audio hardware even if Cubase is running.
PREREQUISITE
You have set other audio applications that access the audio hardware to release the audio driver.
PROCEDURE
- Select Studio > Studio Setup.
- In the Devices list, select Audio System.
- Activate Release Driver when Application is in Background.
RESULT
The application that has the focus can access the audio hardware.
Hi, thank you for replying. I have tried this and that did not work out for me. I also forgot to mention: i dont get any sound in my speakers from my pc even when cubase is not running. When i select my pc speakers it is sound, so there is sound. I have also tested with my old presonus itwo interface, and that one works. Only midas mixer is not working with my pc
This information is essential for troubleshooting. You should not leave it for after the suggestions are made! This is a whole different problem and requires a different approach…
Check video from @Grim .
Also change the title, it is not a cubase issue, its your mixer. You better post on Midas community and search through web for similar issues with your mixer. Better description next time please. Good luck