I rolled back to Ipwich, too. No playback problems so far.
 
 

Do you know your hardware firmware version? Is it the latest?
 
 Windows PnP driver for Fireface UFX, 802, UCX, UC and Babyface/Pro, version 1.089.09/28/2015driver_usb_win_1089.zip
 
Windows Flash Update Tool for Fireface UFX, 802, UCX, UC, Babyface. Update to firmware revision UFX: 357/159/344/26, 802: 13/7/7/7, UCX: 46/240/27/10, UC: 123/135, Babyface: 223.10/06/2015fut_usb_win.zip

My driver version is 1.089 and hardware Revision is 357.
I replicated problem with older drivers, too.
 
 

Maybe this will not solve your problem, but RME doesn't recommend enabling MMCSS except for some DAWs e.g. Cubase / Nuendo.
So disabling MMCSS in the UFX driver settings and in SONAR shouldn't hurt, I think.
 
Another try:
Reduce the available WDM Devices in driver settings to 0 (if you use the UFX in ASIO driver mode).
 
Best,
Klaus

Jamaica Plan + RME UFX = lost connection to audio interface. Anyone else?

 
Nope.

Little change to the problem description: I think SONAR is NOT losing connection to audio interface but it crashes for some other, still unknown reason; maybe some untested combination of project settings or SONAR/system settings.
 
Today I have worked with the same projects than yesterday and there have been no crashes at all. The only change I made was rolling back from Jamaica Plan to Ipwich. I wait forward to see how the next update works.

bapu

Jamaica Plan + RME UFX = lost connection to audio interface. Anyone else?

 
Nope.

If only they gave awards for the most insightful posts:)

panup
Has anybody else seen Jamaica Plan losing connection to ASIO driver? I mean it stops playing audio but playback cursor is still moving forwards and you can't stop it. The only way to get out is to terminate SONAR process in Task Manager.  If I turn power off and back on from UFX, SONAR sees that new audio interface has been detected and asks what to do. Clicking Yes does not heal the problem nor stop playback as the dialog claims.
 

Since post #2 reports this for a different audio interface, we might be seeing one of those problems that have been there for a long time but only appear to a bigger audience after a major update ...
 
Panup's description matches what I have experienced over the past 2 years - occasionally, and less frequently recently. Different interface (vs700, octacapture), though, but Sonar losing connection to the audio driver, playback rolling, meters jumping, but no sound ... if you manage to close, it hangs in task manager, usually requiring a reboot.
 
Now with this showing up with RME interfaces, we get a good chance that Noel will track it down and provide another bunch of optimizations on top of that -  so please, if you have reproducible cases, keep submitting them!

I'm using the same driver and firmware versions that you are, Panup, and I'm not having a problem.

I've got a UFX on Win 10 Pro x64 and no problems with Jamaica Plain.