Is there a way to randomize or shuffle clips in iMovie 10?
You cannot shuffle clips once added to the media library. However, you surely can shuffle the sequence in which you are adding the clips to media library.

To shuffle pics when I try to create a slideshow, I do this:

Assuming all your pics are in my_pics folder

Open Terminal, then:

cd my_photos

mkdir -p random

for filename in *
do
   cp "$filename" ./random/"$(( $RANDOM % 1000 ))_$filename"
done


This will randomize the list of photos in your mu_pics/random folder, which you can then drag into your iMovie.

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