I just ran the command center and I can no longer open sonar...it starts to open then ask about my sound device asio settings then absolutely nothing! If I go into task manager it shows as a process that is running but there is nothing on my screen! I have uninstalled and reinstalled to no avail....all my other programs open just fine!

Have you tried reinstalling (or updating if necessary) your audio interface drivers?

try running as administrator (it runs under different profile, so it doesn't look at your current settings),
it's obviously not a fix, but can narrow reasons for the problem

This has happened to me in the past.  Just go into task manager and end the running Sonar task, it should work fine after that.

I had this same thing happen after an update. It turned out Sonar didn't like (or was trying to use) the built in audio and mic jack on my USB hub. I disabled them in device manager and Sonar opened after that.

Thanks for the suggestions. Indeed the update screwed up my soundcard settings. I went into device manager and disabled my interface which allowed me to open sonar and change the settings for audio devices.  All is back to normal now!

Do you happen to have Windows also using your audio interface for the Windows Default Audio Device? I am wondering if perhaps Windows and Sonar are in conflict over access to a device that uses ASIO drivers.  (the ASIO spec seems to be written to allow a single application/process to have control of a device's ASIO drivers at a time).
 
Bob Bone