Can't find this menu option [Solved]

Try right-clicking on the clip, select the "Associated Audio Files" option http://www.cakewalk.com/D...N&Req=Dialogs1.20.html or open the clip in the loop construction view and the open the Clip > Loop Properties http://www.cakewalk.com/D...&Req=Dialogs2.141.html

I just blow away the cache myself

Thanks both. So I tried the both methods, which worked and removed the Busy sign. But strangely, after I saved the project, restarted Sonar and reopened the project, the sign came back. This is really weird because, as I said, the waveforms were displayed without problem in the first place.

I've hardly done any audio recording since I upgraded to the X series, so I'll do more recording to see if this is going to happen very often.

The project has two audio tracks (guitars) and their outputs are assigned to the master bus and I hear the guitars without problem. But to identify the cause of the problem, I now deleted all tracks and buses (even the master bus) except for the two guitar tracks and assigned the outputs directly to the stereo input of my audio interface (Quad-Capture 1-2).

Then I performed the "Recompute Pictures" to the guitar tracks and saved the project and exited Sonar. Now, I restarted Sonar and opened the project, and the "Silent Buses Detected" dialog box appeared (which didn't appear before), which says the two guitar tracks are currently assigned to a silent hardware and they will be silent. I clicked OK and loaded the project and hit the play button.......I still can hear the two guitars without problem (except for the Busy sign that once again appeared ) 

I need to do more testing. Anyway, thanks for the help.

Thanks Karl, I thought I deleted all sends, but instead of clicking "Delete Send", which I fail to located because it's listed at the bottom of the menu, I selected "--- None ---" from the pull-down. So this time I clicked "Delete Send" and deleted the "none" send (I wonder when and what you use this "--- None ---" option for) and now the "Silent Buses Detected" error message no longer appears. Good. But the "Busy" message still recurs after I perform the "Recompute Pictures" command. Strange.

Thanks Karl. Will start a new thread on this Busy thing. Still can't solve it.