My interface as with all my gear is connected to a good surge/power conditioner that is connected to a UPS that is connected to a voltage regulator. I think I have my equipment fairly well protected.

I use this unit 3 days a week about 8 hours each day. Unit is turned on before the PC and turned off after PC is off. Unit has been working flawlessly since I bought it in November 2019 and can't imagine why it's failing to work now all of a sudden.

When I turn on the unit it goes through its normal startup lights then the lights go off and only meter screen is on, no Host light. My Arc also goes through its normal initialization but does not function as I programmed it.

Totalmix does not appear anymore on the taskbar and does not show up in Windows task manager or Windows Apps anymore even after installing it again. It also does not show in device manager anymore either.

I tested with two other USB cables I use for my keyboards in every USB port on my PC to no avail.

I decided to connect it to my other PC. I installed the driver and connected the unit and got the same result, Still no connection in any UBS ports, no Host Light and Totalmix is not loading on the taskbar, task manager, or seen in device manager and Windows Apps.

I Factory reset the unit and still no connection. The unit is not in CC mode.

With the unit not connected to a PC I set one of the mic inputs to instrument and tested a guitar and I got a signal though I don't know how to get the sound out of my monitors or headphones. I never used the unit as a standalone. My Arc has stand alone functions.

I then tested a mic preamp using both a ribbon and condenser mic and they are working.
I'm guessing the USB port on the unit decided to die.