I have a strange problem. When I want to export my most recent project from iMovie to iTunes, the process stops and forces a reboot of the computer. If I export to a movie file, iMovie crashes. Each time. Now the funny part. I run OSX El Capitan 10.11.6 from external SSD on a 2012 basic Mac mini with 16 GB, which works normally fine. This allowed me the following experiment: I removed the SSD and plugged it into a Macbook Air (2013 base model) and booted again from the external SSD, but on the Macbook Air. Then I exported the project without problems! So, somehow the internals of the mac mini like processor or RAM seem to be the culprits? Has anybody an idea what might be happening? An how to fix it? Thanks in advance.