I am using iMovie '11 on my MacBook Air. I am editing two video sources (used to capture the same action from different angles) together into one video, using the audio from one video source as the source throughout. This involves inserting Video B in place of Video A, and then detaching Video A's audio and expanding it so that it syncs up with Video B. I always detach Video A's audio, thus muting the clip's audio and creating an editable version of Video A's audio that I can then stretch out to sync with the inserted Video B footage.
Except now when I detach Video A's audio, it mutes both the clip AND the detached audio. The audio is still at 100% (I can see the waveforms too). It is not muted, as I tried muting and unmuting it. I have shut down iMovie and restarted it, as well as restarting my computer. None of this is fixing it. And it's vexing, of course, since I haven't changed any of my editing methods and this problem has just arose, and it's never happened before.
This is a fairly time sensitive problem. Does anyone have an idea?