Not sure what is going on.  Octacapture shows up in Device Manager, works for YouTube and windows media etc.  Just nothing in Sonar.  I get the warning for no audio when I start up, and it W\wont show up in Preferences either.
 
Any ideas?  I have restarted both comp. and Octacapture.

Try..

Delete AUD.INI (google for details).
Update Octacapture firmware to latest.
Uninstall drivers/reboot/reinstall latest driver (regardless if you are on latest version or not).

Moving on from that...

Update motherboard BIOS and chipset drivers.
Run windows update.

FYI.  I have the same issue with my Roland Quad Capture.   Probably related to the Roland drivers which are the same on both interfaces, I believe.    After staring up my computer each day, Sonar rarely ever see my Quad Capture on the first launch.  To get it working, I have to re-boot my system.    After that, it works fine.
 
Thank god that UAD has finally announced a USB 3.0 version of their Apollo Twin.  Sweetwater is taking preorders.  I'm saving up my pennies.......
 
Soon my nemesis....Quadcapture....will be no more.......Muuwaaahhhhhh!!!!!
 
The Presonus 192 USB 3.0 interface also looks good........

Yeah, I bought a RME UFX - ex-Quad-Capture -  and have never had the same on-going 'no audio drivers' issue when starting Sonar, nor the infamous 'driver-hang' when Sonar stops working or crashes. Good riddance to Quad-capture...works fine though as a windows player though. Lol!
 
That Apollo sounds pretty cool though! USB 3...whoa!

rebuilding the aud.ini did the trick.  I have had no issues with the Octa until this.  Strange.  Oh well, I'm back and running now. thx for the help.

sven450
rebuilding the aud.ini did the trick.  I have had no issues with the Octa until this.  Strange.  Oh well, I'm back and running now. thx for the help.

Second report of this in the last few weeks with same resolution. I'm not sure why it's just happening with Octacaptures all of a sudden unless you are on Windows 10 (your sig says 8.1) I suspect this won't be the last report. 

I have an Octacaptue working without issue under Win 10. A known problem with these interfaces, though, is that they don't get along with USB3 ports or USB hubs - other than that, they work great.

irvin
I have an Octacaptue working without issue under Win 10. A known problem with these interfaces, though, is that they don't get along with USB3 ports or USB hubs - other than that, they work great.

 
I've got my Octa-Capture connected via USB 3 and haven't had any problems after I built my new PC and installed Windows 10 Pro on it.  The only problems I've had since Windows 10 is that my Motu Midi Micro lite has to be plugged in after the computer starts or it will take up to 5 minutes to boot the system.  This is something Motu has to address with the drivers for the Micro lite for Windows 10.  All other devices work well with the computer and Windows10 plugged in via USB or through the OCta-Capture.

I'm running my Quad Capture via USB 3.0 and Windows 10.  I still have the missing Interface error on the initial start up each day.  Someone suggested a different USB cable a while back.  Going to give that a try.

Doktor Avalanche

sven450
rebuilding the aud.ini did the trick.  I have had no issues with the Octa until this.  Strange.  Oh well, I'm back and running now. thx for the help.

Second report of this in the last few weeks with same resolution. I'm not sure why it's just happening with Octacaptures all of a sudden unless you are on Windows 10 (your sig says 8.1) I suspect this won't be the last report. 

Forgot to update sig.  I am running win 10...