Just had this happen with my Duo-Capture EX.  I was in the middle of copying some midi tracks into a new project and got a popup saying it's no longer available.
 
Actually I thought I had this solved.  Since the most recent win 8.1 update I've been having issues with USB ports shutting down.  I realized that having all the power options...that are accessible through the control panel...set so nothing will ever shut off,  does not affect usb ports through the device manager.  I went through all the usb ports in the device manager and turned off the power management options there.  Originally my computer keyboard started shutting off which alerted me to it.  Then both Sonar and FL Studio started loosing connection to the Duo Capture EX, then I started loosing the connection to my Roland A800Pro.  Turning everything off in the device manager, I thought, fixed it.
 
I did install the pre release recently, and this immediately started happening.  But it was running so rough on my system I rolled it back to the normal 05 version.  I figured by now the 06 update would be fine.  And it does seem to be running great.  I ran FL Studio for several hours last night and no issues.
 
I keep win 8.1 up to date monthly and also my keyboard and soundcard drivers.  I just updated to the latest Sonar Professional (2016.06) a couple of hours ago and it's back.  I don't remember this happening on .05...  At this point I'm just confused and tired of fighting it.
 
 
Reboot is the only thing that works for me until 30 min later when it's gone again. 

same issues, evidence points to the Roland drivers.
 
1. I have Share drivers selected in Preferences, but sometimes switching in/out of Sonar to check something on another app will drop the QC in Sonar. Everything audio still works outside Sonar. 
2. restarting Sonar gets me back up and running. Haven't had to reinstall the QC drivers in some time.
3. just in case, make sure the sample rate setting for the QC is the same as the project you're loading. 
 
Win 10 / x64 / latest updates / latest Sonar Pt 

I've an old UA101, the predecessor to the capture range. Originally an Edirol interface rebadged "Cakewalk" when Roland owned Presonus and Cake, with drivers supplied by Roland.

Back when I used it, every once in a while it would lose connection with Windows in what sounds like exactly the same way as is happening here. Shutting down Windows, switching the interface off, rebooting then, once Windows had loaded the desktop, plugging the interface USB cable in and switching it on usually persuaded Windows to report it had found a 'new' audio device and load the drivers.

I eventually pinned the problem down to most likely being an intermittently failing USB socket on the interface. If the USB plug in the interface was wobbled a little bit in the right way the USB light on the 101 would blink and Windows report it had lost contact. Once contact was lost it often required the reboot procedure above to get things working again.

Zo
 
AUD ini : by deleting this you will force soanr to rescan and re set up your audio devices / set up
 
Audini , you can open it txt and see what is listed and some set up settings if i recall well ....

This has helped me with my quad in the past

tlw

I eventually pinned the problem down to most likely being an intermittently failing USB socket on the interface. If the USB plug in the interface was wobbled a little bit in the right way the USB light on the 101 would blink and Windows report it had lost contact. Once contact was lost it often required the reboot procedure above to get things working again.

 
I have this problem on a few usb ports now. I'm suspecting my cat has has some fights with the usb cables when I've been out.
 

Just thought I should mention this.  I updated win 8.1 today, was just security updates.  AND I changed my Duo-Capture EX from 44,1 to 48,
 
Not a single problem.  Everything is running better than ever on a project with full orchestra and 6 altiverbs.  Audio engine is rock solid.

The first step to confirming it's a driver issue is this: when SONAR hangs shut down and reboot your Capture interface. If it still won't work, it's a driver issue. The only solution is a cold boot. Sorry, but that's what it take sometimes. The Capture interfaces are notoriously finicky in this regard.
 

Veets
Hi,
 
I loaded Sonar Platinum and received a pop up message that says, There are no audio devices for the current driver model on your system. Please go to Edit | Preferences | Audio | Playback and Recording and choose a different driver model.  I don't know what happened as the Roland always worked with ASIO.
 
Does anyone know what I can do to get it to work again on ASIO?  I haven't recorded in a while, I thought about doing a system restore, I am on Windows 10, but I can't remember when I last used Sonar Platinum.  I finally had some quiet time and wanetd to record and now can't.  Thank you for your help!

I used to have this happening all the time when I was using quad with Sonar. No amount of support from Roland - nor CW tech support/forum suggestions stopped it from happening - although some suggestion provided some good workarounds.
I ended up buying an RME UFX and that fixed it! Anyway, this is of course a very expensive solution, so this is what I used to do to get this 'temporarily' working again...
 
When I got the message about no drivers, it was usually because the drivers either hadn't loaded when Win started, arbitrarily dropped out, or they had hung from a previous Sonar project. I would shut down Sonar, unplug the Quad and disconnect my midi keyboard - assuming it was already loaded. Usually Quad would reload the drivers and you're good to go. If the drivers haven't been released from a previous project, then first check Task Manager to see if that's the case...once confirmed you'll then you'll need to still unplug the Quad etc, and wait to see if Windows releases them. If so, you're good to go - it can take 2-5 min sometimes. If you get tired of waiting then try a log-off before rebooting, as that sometimes works...if not, then I'm afraid it's a reboot...in a reboot, you might try to see whether Quad connection works better pluged-in, or left unplugged during reboot/startup. 
 
I use my quad now for general sound, wave playing, even mastering with Ozone and also playing Kontact/Maschine standalone and rarely have any faults...it's just appears to be the relations between Win, Sonar and the Roland drivers. 
 
Good luck!
 
PS. still pissed at Roland for not fixing this and/or working with Cakewalk.

I get this with my Quad Capture, a reboot always fixes it.

A re-boot does absolutely nothing to get my drivers back up in Splat. All other audio works after the crash in Sonar. The only way I have been able to get them working in Splat again is to uninstall, get online and let Windows Update reinstall the drivers. At first I thought it was just an incompatibility  with Mixbus so I completely removed Mixbus 3 and the problem still exists! All I would like is to be able to download and store the installation package for the Windows 10 driver so I don't have to go online everytime I lose my drivers!!!!
There is a hack for the 8.1 driver that I have done but I am afraid to use a hacked driver!! Oh, well! I guess I will give it a try next time they go down.