iMovie 2.1.1 for Mac OS X: Scrambled Thumbnail Images in the Timeline

Symptom

Thumbnail images for clips may appear garbled or scrambled.

Solution

The thumbnail is a visual representation of the media contained in your clips. The symptom described above is cosmetic, and does not affect your video content. Apple is investigating possible solutions for this. If you
split the clip again, the first clip will keep the scrambled thumbnail, while the second clip generates a new thumbnail.

To work around this behavior while keeping the same clip length, you can apply an effect such as Brightness/Contrast, with flat settings, so the clip and its thumbnail are re-rendered.

1. Select an affected clip in the Timeline. (See Figure 1.)




Figure 1 An affected clip

2. Click Effects.
3. Choose an effect like Brightness/Contrast or Adjust Colors.
4. Choose a setting which most closely matches your current image. (See Figure 2.)




Figure 2 Selecting an effect

5. Click Apply. The clip and thumbnail will be rendered again. (See Figure 3.)




Figure 3 A re-rendered clip