I would like these three elements all to work on my computer with little or no tweaking from me: Sonar Platinum, Sound Forge 9, and system sounds (like internet streaming). I have made the Scarlett 6i6 the default device for audio and unchecked the "exclusive control of this device" box. So far (two days) I have only been able to get acceptable latency from the Scarlett by setting the sample rate to 96k, so that's what I have done. As it is right now, Sonar audio is working fine, and so are system sounds and streaming from SoundCloud, etc.
 
But Sound Forge won't play. It throws up this message: "Device sample rate could not be changed because the following applications are playing audio:" That's it. It doesn't name the offending applications. After clearing the first error message I get this second message: "An error occurred while starting playback. A device is not available." (Note: The title bar of both these messages references the Scarlett interface.) In Sound Forge Preferences|Audio the Scarlett is the selected playback and record device. When I open that dialog the sample rate is set at 44.1k, but when I close the dialog an error message says the same thing as when I first try to play a file, to wit "Device sample rate could not be changed because the following applications are playing audio:" When I reopen the dialog the sample rate has been changed (not by me) to 96k. Either way, Sound Forge will not play a file.
 
At this point, Scarlett Mix Control won't allow me to change the sample rate to 44.1k or anything else. Closing Sound Forge still won't allow me to change the sample rate. If I close Sound Forge and Sonar, then I can change the sample rate to 44.1k, reopen Sound Forge and play files. System sounds and streaming audio work, too. I can then reopen Sonar and that works, too, but  Sound Forge stops working with the same errors as before, only now it occasionally names the conflicting application as "audiodg."
 
So everything works, just not all at once. Can someone tell me what I can do to get everything playing nice together? I should note that for years I used a simple M-Audio Audiophile 2496 PCI card, set at 96k/24 bit, and everything worked without having to change settings between applications.
 
For those viewing on phones, my setup is: Sonar Platinum "E"/64 • Win7/64 • i7/2600 • 16GB RAM • Focusrite Scarlett 6i6 • NVIDIA GeForce 8400GS

I would contact Focusrite support on this one Larry. I've never had an issue like yours but then I use Wave Lab and I mostly use 44.1 
I do have some older 48 projects I have been working on without issue. And my routine is to export them at 44.1/16 and open in Wave Lab. I leave Sonar open while I do this just in case I need to return and re-mix. 
My 6i6 seems to play everything I toss at it. 
I did have a problem in the past with my Tascam not liking sample rate changes.If I returned to Sonar after playing in Media Player my songs would be 2 steps lower. 
But the 6i6 has been rock solid. So mabey Sound Forge is the problem. 
 

The first application to latch onto an audio interface will lock it, so even if used by other applications they need to match. Check the sound card settings in Windows first, and set the preferred rate there. Windows should allow the sample rate to be changed by another program, but the first to get it "locks" it. From that point another program must have that sample rate set to use it. If using 96K, try setting both Windows and Sound Forge to 96K for defaults as well.

First, thanks guys for your responses. I was starting to think I had scared everybody away with my convoluted description. 
 

Cactus Music
I would contact Focusrite support on this one Larry. I've never had an issue like yours but then I use Wave Lab and I mostly use 44.1 
I do have some older 48 projects I have been working on without issue. And my routine is to export them at 44.1/16 and open in Wave Lab. I leave Sonar open while I do this just in case I need to return and re-mix. 
My 6i6 seems to play everything I toss at it. 
I did have a problem in the past with my Tascam not liking sample rate changes.If I returned to Sonar after playing in Media Player my songs would be 2 steps lower. 
But the 6i6 has been rock solid. So mabey Sound Forge is the problem.  

 
Cactus - The mixes I want to play in Sound Forge are all at 16/44. The first time I go into the SF audio preferences dialog it shows it's set at 44.1 and it won't play. The next time I open that dialog it shows 96, but it still won't play. Maybe Sound Forge can't handle 96k? Seems crazy for a "professional editor. When I get back to the DAW I'll try opening nothing but Sound Forge, and see if I can change the sample rate that way. Or maybe there's an .ini file or something like that I can configure to set the sample rate as the program is opening. I think I'll also take a look at WaveLab - thanks! For what it's worth I have not had any problems with pitch change due to sample rate mismatch. (PS: I wish I could run at 44.1, but the latency goes up over 20 msec. if I do.)
 

mettelus
The first application to latch onto an audio interface will lock it, so even if used by other applications they need to match. Check the sound card settings in Windows first, and set the preferred rate there. Windows should allow the sample rate to be changed by another program, but the first to get it "locks" it. From that point another program must have that sample rate set to use it. If using 96K, try setting both Windows and Sound Forge to 96K for defaults as well.

 
mettelus - You describe my issue exactly. I have already set Windows audio to match the 96k sample rate in the Scarlett driver, and the result is both Sonar and system sounds are working together nicely. I can't find a way to set Sound Forge to the matching sample rate. It seems to be "stuck" at 44.1k. If I close everything else and set the driver to 44.1k I can use Sound Forge. Otherwise, no.
 

OK, got it working. In Sound Forge|Options|Preferences|Audio, I deselected "Focusrite USB 2.0 Audio Driver" and selected "Microsoft Sound Mapper." Kind of unintuitive, but whatever. Trial and error indicates that probably any choice would have worked except for the one I chose first. (I did try "Windows Classic Wave Driver" and that worked.) Thanks for your input, gentlemen.