You can use ASIO4all with your interface, but we don't recommend using ASIO4all in your DAW for your Focusrite Interface. Our interfaces already come with a native device-specific driver that includes both ASIO and WDM driver types. Using ASIO4all can result in much slower latency and worse performance than the native ASIO Device Driver.
ASIO4all is actually designed for units that don't have native ASIO Device Drivers, like your computer's built-in audio (for example, Realtek or Nvidia HD Audio, SoundBlaster cards). When you use ASIO4all, you're bypassing the manufacturer's own ASIO Device Driver that's specifically written for that hardware.
While we are aware ASIO4all can fix some issues, in general, we'd still advise against using it.
So, please always select the correct device driver for your Focusrite Interface, which should read “Focusrite” or the unit's name such as “Scarlett,” “Saffire,” “Clarett,” etc. For more information on ASIO4all, please see the ASIO4all FAQ page here.
For more information on ASIO4all please see the ASIO4all FAQ page here. You can see in this article that ASIO4all makers do not recommend installing the manufacturer driver for your USB unit, the same as we don't recommend installing their software. Please do not run ASIO4all with your Focusrite unit, as these are not meant to be compatible.