Hi there,
I don’t know if this is the same problem as you are having – but I just had a similar thing and it turned out it was a clip conforming issue.
I updated to 6.0.2 and all my audio vanished, waveforms, clips, everything.. I noticed at the bottom that it was conforming all the clips again (I’m using MXF’s recorded on a Canon C300). Once they had comformed the relevant clips the audio reappeared. It was quite quick for me as I am running a powerful machine with 48gb of RAM, it may take longer for others – but I’d check that your clips are simply still not comforming before try anything more drastic. Especially if you’ve recently done an update or something which has changed the media.
Good luck,
Gavin.