IMovie Can't See Your Camcorder When it's Connected - iMovie '11
From Help Wiki
Quick Suggestions
- Check to see that your camera is compatible with iMovie
- If you are using a DV camera, try connecting with a FireWire cable instead of USB.
- Check to see that your camera is powered on and in the correct mode.
Additional Help
- Apple Support: If iMovie doesn't recognize your camcorder.
- Apple Support: Cannot see or control camera.