My UA 25-EX keeps vanishing in Platinum. There seems to be no rhyme or reason. It works then vanishes.
 
I re-installed the driver. No love.
 
In Preferences it does not show as an audio device yet it's there as a MIDI device.
 
I still have X3 on my DAW. The best part is that it shows and works on X3 but not in Platinum Nweburyport.
 
I'm stumped.
 
Still running Win 7 x64.

Just a shot in the dark...
 
Being a bus-powered device, the UA-25EX lives and dies by the USB port it's connected to.  Maybe try a different port?
 
(I don't know why X3 and Newbury would see the port differently, but you never know).

Dave, I sent you a PM.

I have the same setup and have no problems.
 
Broken USB plug/cable/UA25-EX?

I just went thru this and even had Sweetwater trying to help me troubleshoot it, but answer came from a tech geek. Windows 10 power saving mode- "balanced" will randomly shut off USB ports if it thinks that too much power is being used. You must go into your Windows system settings and turn off the any power saving selected and tell Windows to stop butting in. I went thru awful weeks until this simple solution presented itself. I hope this helps and is also what's going on with your audio interface.