Is it possible that you did something with the re-size setting scale of the wave file.
 
You can scroll on the track scale on the right of the track to make it bigger or smaller
 
Maybe this is it??@#$@??& LOL
 
Cj

ooooh - good point CJ
 
I have accidentally done this when trying to zoom using the mouse scroll wheel and the wrong modifier key
 
I can see how it would be really easy to zoom right out of the waveform without realising giving these exact symptoms
 
If I were a betting man...

nope. tried that. (but good idea!)

weirdness. I just got it.
I changed the picture folder/path from the c: drive to the d: drive and voila! it worked.
 
now to figure out what the permissions deal is on c.

Are you saving your audio and tracks to your D: drive in preferences? This could be the problem.

I have projects/audio and picture cache on separate drives - not a problem and pretty common I would think.
 
 

Same here, that's my typical setup: picture cache on C: and projects on D:
 
It does sound like a potential permission issue in that specific folder on the C:    It's possible that a folder at the root level might not have the same issue.
 

I had the same problem today, with only one project so far. I know I could see the waveform in track view after I recorded it yesterday, but upon opening the project today, there was just a straight line in the track view. I could still hear the audio on playback, but just a straight line as I've said. Pointing the picture cache to D: drive in preferences solved the problem for me as well. Audio was visible again after restarting X3. Thanks to soundsubs for the fix.
 
P.S.: I also save my system files on C: , and my audio on the D: drive.