This may be a simple settings fix.  I use a Kemper Profiling amp for my guitar into SONAR.  Recently, Kemper released a "Rig Manager" librarian profile manager.  In addition to managing amp profiles Rig Manager also lets me preview profiles very quickly.  I simply select a profile and play my guitar and it sounds in SONAR.  Or, at least it should.  What's happening is that once I click on the Rig Manager app window SONAR goes mute...no sound anywhere.  I have to go to the SONAR app window and click on it and suddenly the audio is back on.  If I then go back to Rig Manager the sound again mutes in SONAR..so on and so on.  I checked in Windows sounds and saw that I have it set to share the audio card.  Should this be turned off or ... ? 

Preferences > Audio > Playback and Recording "Share Drivers With Other Programs"

scook
Preferences > Audio > Playback and Recording "Share Drivers With Other Programs"

OK...should it be to on or off.  Rig Manager does not actually have an audio interface so it depends on the DAW to play the audio.   

It turns out that I have to turn audio driver sharing OFF within SONAR to resolve the issue.  When the setting is set to share SONAR releases control of the audio card once a different app is brought into focus.  Since Rig Manager does not have an audio interface and must depend on the DAW (SONAR) for playback the audio driver must remain under SONAR control.