audio waveforms disappeared, and some clips greyed out

I've been Googling for answers to no avail. I'm not sure what's going on here or how to fix it. The audio plays fine but I can't see the waveforms, and a few clips are greyed out. What did I do and how do I fix it? Thanks!

In the Timeline View Options drop-down enable the "Audio Waveforms" button - this is disabled in your screenshot.

Clips with processing applied are usually displayed with a darker shade of the Clip colour.

Click on the Clip and open the Inspector and confirm that Clip Gain (Volume), Pan, Pitch, and Equaliser settings are the defaults and that no Clip-based plugins have been applied.

The Inspector's Additional Options (3 dots) menu provides "Reset All Audio", "Remove All Audio Effects", and "Remove and Reset All" options to return the Clip to its default state.