Hi there, after a lot of initial research and effort I am hoping the community can help.
I found over the last week that both new and previously transcoded .MOV (GoPro Cineform) files lost all audio in my projects. I found this while importing new clips into a new project, and then went back to check if old projects/clips had the same issue. The waveforms are not present, and the audio bars don't show any level while playing back files in source or on the timeline. The files aren't corrupted as some of the projects were completed and played/exported audio fine. In other words the past projects had waveforms, audio, and no issues prior. I don't think this was a result of me updating the program to a newer version, my version was stable over the last few days when this happened. Also, h264 and h265 MP4 clips have audio, waveforms, and play fine still.
So far, I tried:
1) Clearing the media caches as well as creating new media cache folders
2) Resetting all preferences as Premiere launched
3) Toggling Make Offline and Link Media on the clips
4) Installing/uninstalling Premiere and tried on V13 and newest V14 versions.
5) Going back to a system restore point roughly the time before I experienced the issues.
There are probably a couple other steps in there I tried to no avail. The last thing I saw was the Creative Cloud Cleaner, and was considering running that next.
The only thing I can come up with is maybe the audio codec required for these clips got corrupted as a result of installing other pieces of software or something? Hence me trying a restore point.