signal flutter on playback and input

I am not sure how this occurred, but it began only a few days ago, after the latest Windows 10 update forced me to call “my software vendor” for tech support, when Dorico 'disappeared" my eliscence (again) and (also) Windows knocked out my Steinberg UR-12 driver from my Dorico device setup menu.
I called for support and had both these problems “;lleviated”- however when I play back some Dorico files, or I try inputting a note, I hear a “flutter” over the duration of the input note-sound, or I hear one over the ENTIRE playback of the file. What is causing this and how can it be rectified so I do not hear this any longer? It’s frustrating, because I cannot write the music without the flutter, nor do the files play back without it. EXCEPT- on one file, which was the first I was listening to when it started, somehow, I do not know how, I eliminated the flutter and it plays fine. however, the new score I am working on seems to flutter on input, and also, when I play it back.
The tech support people who helped me (at Sweetwater, where I bought Dorico) replaced- is that he word- the UR-12 device driver with something called a “ASIO4ALL v2”. The UR 12 is still my default audio playback on the PC, although now of course the UR 12 Driver is not an option on the device setup menu for playback. None of this happened before the “ASIO4ALL” was installed, and as far as I know they told me everything should still be fine, to play back other applications or from the internet except, that Dorico files (some anyway) are now riddled with this issue.
I would like an explanation and/or a solution, because I can’t progress at all on my work if this problem is continual.

What you describe sounds strange.
First of all, ASIO4All is a general purpose ASIO driver that works with virtually any audio interface (be it external interfaces like your UR or built-in soundchips.)
But it’s main purpose is for audio devices for which no dedicated ASIO driver exists. There is a special driver for the UR and you should use that one.
You say it has disappeared since the latest Win update. Have you tried reinstalling the driver?
If you don’t have the installer anymore, you can download it from here:

Next, that fluttering. I can’t imagine how that sounds like. What if you do an audio export (in Dorico choose File > Export > Audio) of one of the “fluttering” projects, does the exported audio also have the fluttering. If it is also fluttering, could you please post it here (after first zipping the file) or send it to u dot stoermer at steinberg dot de

I’ll email you with a private message Ulf.