On Windows systems, you can check in Device Manager to see if your interface is being detected correctly by your computer. To access this:

• Right-click on the 'Start' icon > Device Manager.
• Focusrite interfaces should appear under both: ‘Sound, Video & Game Controllers’ and 'Focusrite Audio.’  

If your interface is not shown in Device Manager, please try the below steps.

1. Ensure your Scarlett is connected to your computer's USB port. If your Scarlett is connected via a USB hub, try connecting it directly to a port on your computer instead.
2. Try another USB cable in case the one you're using is faulty, ensuring it is less than 2 metres in length
3. [2i2, 4i4, 16i16, & 18i16 only] Ensure the USB cable you're connecting to the computer is connected to the port labelled 'USB' on your Scarlett and that it is receiving enough power. More information on power requirements can be found here for 2i2, here for 4i4 and here for 16i16 & 18i16. 
4. If you have not restarted your computer since installing Focusrite Control 2, try restarting it.

We have seen an installation issue that appears on some Windows machines that prevents Focusrite Control 2 from detecting your device. If you encounter this issue, you will likely see the below error message when running the installer:

You may also see the below error when trying to open Focusrite Notifier:

To fix this, please try removing any old Microsoft Visual C++ Redistributable installations using this Microsoft tool: Fix problems that block programs from being installed or removed

The below steps outline how to remove old Redistributable installations with the troubleshooter:

1. Download the troubleshooter via the above link.
2. Run the troubleshooter by double clicking the 'MicrosoftProgram_Install_and_Uninstall.meta' file. This may be located in your Downloads folder.
3. Click 'Next'.
4. Click 'Uninstalling'.
5. Select the relevant Visual C++ Redistributable version and select 'Next'. The version you should select will be flagged in the error message you see when running the Focusrite Control 2 installer:
6. Select ‘Yes, try uninstall’ and wait for the troubleshooter to finish.
7. Now, try running the Focusrite Control 2 installer again.

If you have any other Focusrite software (Focusrite Control or RedNet Control) on your computer, ensure you have the latest version from here - sometimes Focusrite Control 2 will not detect your interface when you have other, older Focusrite software installed.
To check if your interface is being detected by your Mac:

• Click the Apple logo (top left of your screen) > About This Mac > More Info… > System Report (at the bottom of the page) > Hardware > USB

If your interface is being seen at a hardware level, your interface model will be displayed in the main window as shown below.

If your interface is not shown in the System Report, please try the below steps.

1. Ensure your Scarlett is connected to your computer's USB port. If your Scarlett is connected via a USB hub, try connecting it directly to a port on your computer instead.
2. Try another USB cable in case the one you're using is faulty, ensuring it is less than 2 metres in length
3. [2i2, 4i4, 16i16, & 18i16 only] Ensure the USB cable you're connecting to the computer is connected to the port labelled 'USB' on your Scarlett and that it is receiving enough power. More information on power requirements can be found here for 2i2, here for 4i4 and here for 16i16 & 18i16.