No sound from Cubase only - Focusrite Scarlett 2i2 OSX

Cubase Elements 8 was recently installed on one of the iMacs at my school, and aside from the constant random closes, there is a very annoying issue: On loading my project, no output is heard from the program. Is this a known issue?
All levels and inputs are showing up on the mixer, and sounds outside of Cubase are audible (despite my interface being plugged in).
My interface is a Focusrite Scarlett 2i2, and yes, everything is correct in VST Connections and the driver is selected. Curiously, the issue still occurs using the built-in audio too, with all the levels appearing to be working, but no sound from the built-in speakers (but only with Cubase).
I have managed to make it work once or twice by opening my files from file → recent projects, but this rarely works.
Another thing I noticed was on creating a new project, I could hear sounds correctly from the MediaBay.
Apologies for the long-winded post, but any help would be greatly appreciated.
Unfortunately, due to school restrictions and my lack of experience with Macs, I couldn’t figure out what version of OSX it’s running, but I will check again tomorrow.
Thanks!

Hi,

If you can hear the signal from MediaBay, but not from your output, then it’s a routing issue. Could you describe your VST Connections > Outputs settings, and also Control Room (Studio), if you use it?

Where are your tracks routed to (output)?

Hi. Disable control room and route your outputs.