I picked up a VRM Box in the summer and it is really an awesome little tool. However I have noticed that it can cause some oddities to occur on my system when it is connected. Nothing TOO major but enough that I'm getting into the habit of disconnecting the USB cable before I boot up my DAW if I don't intend to do any monitoring through the box.
 
First off I use the VRM Box connected VIA SPDIF to my Focusrite Scarlett 18i6. I am not using it as a standalone interface on my main rig and I am not trying to run both interfaces as separate devices using WDM or whatever mode allows that. The 18i6 is my main interface and I always use ASIO.
 
A few things I've noticed are that when I'm booting up Windows with the box connected via USB (again remember I'm using it via SPDIF but it requires the USB to get power) that the boot takes longer. Windows will start up normally then it's like the computer does a little mini shut down so that my monitor no longer gets a signal for anywhere from 2-20 seconds. It's a little weird. It does eventually boot up normally and nothing strange seems to for the rest of the boot up/login. I think the system does this anyway when booting but it happens so quickly it is unnoticeable. With the box connected it is.
 
The other thing is I think it confuses Sonar a little bit when I'm doing complex, resource intensive tasks. I notice more little quirks while editing and doing stuff in general within X3 which for the most part has been extremely solid for me.
 
So I don't know for sure what's going on or if this is a common issue but I thought I would post a warning to say if you have one of these devices and are noticing little quirks then try disconnecting the USB cable before boot up if you don't intend to use it during that session. It's really only for mixing anyway so there is no need to have it hooked up while tracking, editing, etc. While mixing though it seems to be fine and honestly mixing is the one thing in Sonar that has rarely, if ever, caused me any grief. My quirks usually occur during editing tasks (and as I said most of that has disappated since X3).
 
Cheers.

I find disabling system sounds and making sure the VRM box is not the default audio device for windows helps. But I have a similar setup, different main card but feeding the vrm by spdif also, If I have sonar (or any other daw for that matter) open then I play audio in any other app I get silence from the VRM when I go back to the DAW then need to unplug and replug to get it back. This isn't an isolated issue I have two friends who have the exact same issues. It is a VRM thing not a sonar thing. The other guys I know who have it only use fl studio. I dunno about the other issues you have since the issue I described is the only issue I have ever had with it.
 
EDIT: FWIW I have the same issue with ableton live 9 suite, Ohm Studio & cubase element 7 and the card I feed the spdif from is an maudio delta 66

I used it to mix a complex track in Sonar and when I opened the project the next day most of my ProChannel devices had reset to the default settings. I posted about it on this here forum at the time as it was very freaky.
The box is clever (the Rokit 6 setting sounds like my Rokit 6s!) but I can live without the side effects.

Grum.

Greeny
I find disabling system sounds and making sure the VRM box is not the default audio device for windows helps. But I have a similar setup, different main card but feeding the vrm by spdif also, If I have sonar (or any other daw for that matter) open then I play audio in any other app I get silence from the VRM when I go back to the DAW then need to unplug and replug to get it back. This isn't an isolated issue I have two friends who have the exact same issues. It is a VRM thing not a sonar thing. The other guys I know who have it only use fl studio. I dunno about the other issues you have since the issue I described is the only issue I have ever had with it.

Yeah, what you are describing is Windows (or more accurately the media player you are using) taking over the interface's ASIO driver and not releasing it when you switch back to Sonar. I think if you close the offending program and close/reopen Sonar Sonar will reconnect to the interface. This happens sometimes even with full on fancy pants interfaces because ASIO can only do one thing at once (as far as I know so I don't try to force it nor do I really need to).
 
I personally have the Scarlett set as my default audio device in Windows. If I want to use the onboard sound I just switch to it in the control panel but I never do. Most people don't do things this way (they want both) and it isn't necessary but it works for me and I know that the Scarlett is ALWAYS in charge unless I tell it not to be.
 
I'm still a little sketchy on how all that works though so don't take my word as gospel for that.  

grumbleweed4162
I used it to mix a complex track in Sonar and when I opened the project the next day most of my ProChannel devices had reset to the default settings. I posted about it on this here forum at the time as it was very freaky.
The box is clever (the Rokit 6 setting sounds like my Rokit 6s!) but I can live without the side effects.

Grum.

Really? That's a little nuts. I hope you contacted Focusrite about it. I'll keep an eye out for that behavior but I've never read of anyone else experiencing that. Are you running the VRM as a standalone interface or VIA SPDIF?
 
Edit: BTW... Focusrite support is REALLY good. I sent them an email once and they got back to me within 24 hours. Also they've even popped into threads here on the forum I posted when I was first getting started. I wouldn't be at all surprised if they show up in this one actually. I'm not having any real problems though. Just thought it might help some folks avoid a bit of quirkiness in their projects.

I am also fairly sure thats what is happening beepster, I have mine setup the same btw, the maudio is the boss at all times I have the onboard disabled in bios. I don't really find it a big enough issue to lose  sleep over since if I am working in a daw I rarely feel the need to play audio anywhere else, its at least nice that I can just uplug the vrm and plug it back in and it works again on the odd occasion that I need to.
 
I wonder if allowing the drivers to be shared with other programs via the preferences in sonar would stop it happening but meh I am rambling now, was just adding my 2pence worth :)

I've disconnected mine.  Its now "in a drawer" collecting dust.  I didn't really find much use for it. 

Greeny
I am also fairly sure thats what is happening beepster, I have mine setup the same btw, the maudio is the boss at all times I have the onboard disabled in bios. I don't really find it a big enough issue to lose  sleep over since if I am working in a daw I rarely feel the need to play audio anywhere else, its at least nice that I can just uplug the vrm and plug it back in and it works again on the odd occasion that I need to.
 
I wonder if allowing the drivers to be shared with other programs via the preferences in sonar would stop it happening but meh I am rambling now, was just adding my 2pence worth :)

I think I may have set the "Share with other programs" thing activated and it was mentioned in one of my very early derp n00b threads a few years back. I haven't fiddled with that stuff since then though. I got it all set up initially and haven't had to screw with it since. It all works and was very simple. The Scarlett is an AWESOME interface.

fireberd
I've disconnected mine.  Its now "in a drawer" collecting dust.  I didn't really find much use for it. 

I've always gotten the impression you are really good at what you do though and have a decent set up. I'm still a squealing babe in the woods for the most part and my room sucks so I figure it'll help me get my mixes dialed in better than they have been. Also due to poor soundproofing I mostly have to mix through headphones which is obviously not ideal. I haven't really put it to the test though because I've only had it for a little while.
 
Cheers.

Beepster

Greeny
I am also fairly sure thats what is happening beepster, I have mine setup the same btw, the maudio is the boss at all times I have the onboard disabled in bios. I don't really find it a big enough issue to lose  sleep over since if I am working in a daw I rarely feel the need to play audio anywhere else, its at least nice that I can just uplug the vrm and plug it back in and it works again on the odd occasion that I need to.
 
I wonder if allowing the drivers to be shared with other programs via the preferences in sonar would stop it happening but meh I am rambling now, was just adding my 2pence worth :)

I think I may have set the "Share with other programs" thing activated and it was mentioned in one of my very early derp n00b threads a few years back. I haven't fiddled with that stuff since then though. I got it all set up initially and haven't had to screw with it since. It all works and was very simple. The Scarlett is an AWESOME interface.

Yeah I believe so, I was just about to get one when I saw a used maudio delta66 with the omni I/O breakout box on ebbay and took a punt for a whopping £36! the thing cost £500 when they were new :D Turns out even 15 years later its a hell of a combo for an home setup :D