When I am running any Steinberg program (Dorico/Halion 6/Cubase 9/Groove Agent4) my computer will not go into sleep mode, regardless of if I have (Windows10 Pro) in PowerSaver or HighPerformance mode.
Even screen savers will not come on.
I have other audio programs installed here that do not behave this way.
Is there any way to fix this?
In Cubase, look for the “Use Steinberg Audio Power Scheme” setting that, if activated, might be associated with your concern. It is found in the Devices>Device Setup>VST Audio System menu.
Regards 
If your PC goes to sleep while Cubase is running you can have problems with Cubase communicating with your audio interface after it wakes up. I suspect this is caused by Cubase waking up before the interface does.
OK, I tried that, and edited the new Steinberg power scheme so that the computer would go to sleep after 2 hours.
No luck
Still the same. No screen saver and no sleep mode.
I guess all I can do is just don’t leave these Steinberg programs running.