I'm currently trying to automate Gain in a session, since I find editing Gain vs. Volume allows me to adjust faders after the automation, not that this alone has any consequence to my issue here. One of my sessions suddenly dropped the visual audio (waveforms) in all of the tracks, and I'm not sure if I did something wrong, or if this is a bug. I can hear the audio, but there's no waveform in the tracks, not even the T1, T2, T3 etc. tracks. Nothing is muted, and other sessions don't have this problem. Has anyone else seen this and know what could be the problem? Thanks!

Does it show busy or anything else on the track.

Have you tried recomputing the picture?

That fixed it. Weirdness. Actually, if I zoomed into the track far enough, the waveform appears. Zoom out, and it disappeared again. How it got that way to begin with I'm not sure. Thanks!

Is it in X1 or X2?

Ive noticed that prob in X1 with the Zoom affectin it.

Have ya cleared out the picture cache folder lately?

Glad it took care of it for ya

+1 to clearng out the picture cache.  It is the most common cause of this problem.

If you can see a waveform zoomed in that disappears as you zoom out, that sounds like you've adjusted the audio scaling for that track.

Change it back to default by double clicking on the vertical bar that divides the clip pane from the track header.It's a per track setting so make sure you do it on the track giving you trouble.

You can also adjust it to your own preferred scale by click dragging up or down in the same place.

If it's just a flat line regardless of zoom level just re-compute the pictures as suggested above. (Right Click -->associated audio files or Shift+K)