>My old iMovie 6.0.3 is incompatible with El Capitan, which is a bummer since the changes made after that version eliminated some of the most useful features, such as: useful audio editing capabilities (they took away audio track isolation, audio enhancements and more); basic visual effects like video overlays for green screen, split screen etc.; and time code displays.
I spoke with Apple about this, and a fix sin't going to happen. They want you to upgrade to iMovie 10.
>A workaround for Yosemite is discussed here that I hope works for El Capitan: https://discussions..../thread/6770253
It works, but not well. Quite slow and balky. Fortunately, I have an old MacBook Pro with an older OS, so I can use iMovie 6.0.3 there.