my SONAR Home Studio can't find any output audio device.
Windows 7 Home 32 - bit.
But headphones and speakers are presented.
I have message box about incompatible audio drivers when I open a project.
Thanks
Happy New Year
 

Hard to answer this without knowing if your using an audio interface and asio drivers. 
 
Generally you need to install the latest ASIO drivers from the manufactures web site and make sure this is what Sonar is set to use in preferances. 
 
If you using the on board sound card go to preferances and setect WASAPI exclusive. 

If you are using your onboard computer interface (the one that was shipped with your computer) it is possible that you have your interface set to allow exclusive mode and some other program has got hold of it.  When this happens Sonar can't get to the interface.  Check your Windows settings for your audio interface (If you are using the internal one) and make sure that it is shared.

If you are using an eternal audio interface, make sure that it is pulgged in and powered up BEFORE starting Sonar.
 
Glen

Thanks to all, no problems
Happy New Year