Applies to: Scarlett 4i4 4th Gen
The Scarlett 4i4 4th Gen needs at least 5V @ 1.5A in order to work correctly. All USB-C ports on modern computers will supply this. If you're using a USB-A port, and you haven't got the included power supply connected, the USB icon on the front of the unit flashes red.
The 4i4 may still show up as an audio device in your computer's Sound Settings, however, no audio will go to the 4i4's outputs, and it won't connect to the Focusrite Control 2 software.
Here are some steps you can try if you see this behaviour.
Connect the Scarlett 4i4 to a USB-C port on your computer
If you have a USB-C port on your computer, it will supply enough power to the Scarlett 4i4.
Try a different USB cable
USB cables longer than two metres can sometimes cause issues. Ensure the replacement USB cable is shorter than this. For more information about USB cables, please see here.
Power the Scarlett 4i4 with the included power supply
As well as the main USB port, the Scarlett 4i4 has an extra port on the rear panel, labelled 5V DC, which you can connect the included power supply to if none of the USB ports on your computer supply enough power.
You can find the power supply in your Scarlett 4i4's box.