Hi,
there is no button to turn off UR22 mk2. Is It OK to have device turned on 24/7 ? I have connected one USB to computer and one to power supply.
My previous interface didn’t have an on/off switch either and I let it run 24/7 for years without a problem. If you’re worried about power consumption (USB 2.0 is only 5v) you could go into power settings of Windows and enable your OS to cut power to USB ports when unused but you need to re enable this when you’re working in your DAW.