Relevant mostly to OS X admins
Earlier this week, my co-worker started on a routine user migration from computer.old running 10.9.5 to computer.new on 10.11.1. He booted .old to Target Disk Mode, attached to .new over thunderbolt, and started up Migration Assistant. To his surprise, after authenticating within MA, instead of inquiring “where is our migration source?” the computer exited to loginwindow. We confirmed that this condition was repeatable under multiple circumstances.
We brought our unexpected behavior to the macadmins Slack community, where collaboration in the #osx channel with others who had seen this helped narrow the circumstances down to Profile options configured at loginwindow. Specifically, this unwanted behavior can be induced by enabling Disable Automatic Login in the Login Window section of the Profile. This has been set in our default Profile for many OS X releases, but has now become a problem.
If the Profile is removed, or updated with a version that does not have Disable Automatic Login enabled, Migration Assistant proceeds as expected.
I’ve filed this as Apple Bug #23664591, trackable at openradar.appspot.com.