I upgraded my computer and got a new motherboard and I couldn't use my old Focusrite Saffire Pro since it had firewire and my new motherboard doesn't have a firewire connection so I upgraded to the Saffire 2i4. Now with my old interface I could play a music file in Windows Media Player and then play something in Sonar switching back and forth. With this interface I have to close Sonar to hear what is being played in WMP (or anything else like youtube or whatever). Is there a setting to change this? I never had this issue with my old interface.

I wouldn't regard the 2i4 as an upgrade on the same level maybe (assuming it has exactly the same inputs and outputs). Couldn't you have bought a FireWire card to plug into your new motherboard?

Anyway I assume you have the latest drivers. With ASIO drivers the current behaviour you describe is generally the norm however as you say the saffires somehow bypass this limitation (the drivers are fantastic).

I'm not sure about 2i4's you will have to wait for further comments or contact focusrite. Have you checked the sound settings under windows? (Control panel - Sounds).

The workaround if not possible is to use your internal sound chip inside your motherboard if it has it or buy an additional sound card for your windows sounds (or buy a FireWire card for your saffire then you could possibily run both, you will probably get slightly better performance with the saffire although there's not much in it) .

Did you change your sample rate? If the interface and Sonar are set to 48Khz, but Windows is set for 44.1kHz, then this will cause the problem. Go to Windows: Sound: Playback Devices to confirm that "Speakers" is set to 48KHz (or whatever sample rate Sonar and the interface, i.e. MixControl, uses). Overall, you want them both to be the same.

Okay, thanks guys. Yea I have a firewire card but the motherbaord I have doesnt have a port to plug that card into. I actually think I am running 48 khz in Sonar so that could def be the problem BUT it worked with my old interface. Can Wndows be set to a different khz? I love the Saffie I was just curious about this fix because when I export a project I like to listen to it in WMP to make sure everything bounced correctly. I work with a lot of midi and sometimes things dont export correctly so its great to listen to it while Im editing in Sonar.

Windows does have a separate setting for sample rate in the advanced tab of the properties dialog for the device. The properties dialog can be launched for the device from Control Panel > Hardware and Sound > Sound playback tab. The sample rate should be set the same as in SONAR Preferences > Audio > Driver Settings to have Windows and SONAR play well together through the same interface. Also make sure that SONAR is running ASIO driver mode in Preferences > Audio > Playback and Record. Windows apps typically use another driver so driver sharing should not be an issue.

Okay I changed the rates so they match each other as soon as I open a project in Sonar sound is disabled outside of it. Hmmmmm

Have you also got the "share drivers with other programs" under preferences > Audio > Playback and recording ticked in SONAR?

It is a possibility depending on the Driver Mode selected in SONAR and the other apps. I do not use a Focusrite interface. In my case, I use ASIO drive mode and do not have "Share Drivers With Other Programs" enabled. I have no problem running other windows apps through my interface while running SONAR. My other windows apps do not use the ASIO driver. The exclusive mode switches in the device properties in Windows also do not affect concurrent app and SONAR access to the interface.

I checked to see if I had "Share Drivers With Other Programs" enabled and I didn't so I checked it to see if it would work and still the same result.  As soon as I open a project in Sonar sound is disabled outside of it. 

Certainly in the case with the Saffire you don't need to enable this. Contact Focusrite I suggest and keep us updated.