I have imported some videos (mp4) into my Photos program and I want to use those in making a new iMovie project. I have no libraries showing up in my list. My Photos Library is kept on an external drive. I have that drive attached to my MacBook Pro (running El Capitan) and my Photos app is running. When I go into iMovie (v. 10.1.1), I cannot get it to show my Photos Library for me to select that video. Actually, I can see the Photos Library listed, but it is greyed out so I cannot select it. Any ideas what I am missing? Thanks.