Windows
1. Open Ableton Live.
2. Click Options > Preferences:
3. Go to the Audio tab on the left-hand side of the Preferences window.
4. Set the Driver Type to ASIO and Audio Device to Focusrite USB ASIO:
Mac
1. Open Ableton Live.
2. Click Live in the top menu bar.
3. Click Settings.
4. Go to the Audio tab on the left-hand side of the Preferences window.
5. Set the Audio Input Device and Audio Output Device to your Focusrite interface.
Configuring Inputs and Outputs
After setting your interface as the Audio device in Live, you may need to configure the inputs and outputs. For smaller 2 channel interfaces, this will be configured automatically, but not for devices with higher channel counts. To set this up:
1. In the Preferences menu, select Input Config.
2. Click to highlight the relevant inputs. Configuring this window is down to your specific setup, if you have a permanent setup where you're leaving the same devices permanently connected, you may wish to label the corresponding inputs.
3. Click OK.
4. Do the same for the Output Config.
5. Click OK.
6. Close the Preferences window.
You will now be able to access all of your inputs and outputs in the Arrangement and Session views.