I don't know if this is of any help but my Focusrite connection disappears from time to time (not that often, fingers crossed) but I just pulled the focusrite plug out of the computer then reinserted it to reconnect.
USB selective suspend disabled? Each USB Hub set to not "Allow computer to turn off this device to save power" Tried alternative USB ports....particularly if you have both VST2 and VST3 try the other.
Sometimes a Windows 10 update changes my sample rate in Windows sound settings from my usual 48K to 96K. When this happens my Focusrite sometimes loses firewire connection but sometimes it completely goes down and I get the 'No Hardware connected' message. To get it working again I turn computer off, disconnect Focusrite (power and firewire), turn on computer, re-set Windows sound to 48K, turn computer off, connect Focusrite, turn computer on.
I have checked all the things mentioned, and still no luck. I disabled memory cache on my C drive. And so far, I have not had hardware not connected. And I have not crashed. I get BSOD sometimes. I have never used the fix I did before. So I don't know if the problem is fixed or not. But so far, I haven't had trouble. Have you guys ever done this fix before? Is this something standard that should always be done? And can this cause other problems?
I have a Scarlett 18i20 that will randomly lose connection and when it does, its goes white noise at FULL DBFS!!!! And I swear I'm always on my headphones when that happens. BAMMMM! I stopped using it, put in a ticket at Focusrite. They had no idea why. Everything is up to date. I haven't tried it Since Feb :(