I'm working with some audio tracks on X3 that I have been mixing for some time.  Tonight I tried to work on them and there is no audio.  The project loads normally.  The wave forms show up on the track view, but the meters in the console view show nothing.  Audio engine is on, nothing has been changed (that I know of) since I last worked on the project.  No solo or mute buttons on.  I'm sure there is a rediculously simple solution but I'm darned if I can figure it out. 

Are your speakers on? Are the meters working?

ALways start with the simple stuff 1st. Toggle the mute button, next the solo button, check any busses,  look in preferences and see if your audio card is showing up as an option.  Grab headphones and plug em into the sound card.  If the waves  are there, the audio is still there.  Re-boot the computer.
 

I asked you not to laugh.  Yeah, the speakers are on.  I immediately ran another wave player through my audio device (Presonus Audiobox) and it plays fine......just not Sonar.   Like I said, the wave forms show up in the track view, but no levels showing on meters, track or console view.  Checked the project folders, all audio data looks intact and in the proper place.  These are tracks I have played dozens of times of the last few months.

Thanks Jimbo.  I immediately came up with the same list and have tried each of your suggestions.  The meters on Sonar are showing nothing.

Did you check Preferences Audio Device to see if it is selected? 

Yep, same old AudioBox selected in preferences.

I'm at a loss. The only thing is to try coping to a new project and see if that works. Sorry I have nothing more. 

Check your solo buttons....I had a similar problem and one track was solo'ed and that mutes out everything else. If not that, I'd double check the console view for level and output settings. You may be routed to a buss that's turned down. 

Yep, tried that too thinking that maybe there was a bad link to the audio data or something....no go.  Every project and the new one(s) I created to test it behave the same.  There's got to be that one little check box I'm overlooking.
 
Thanks