It seems an image is created on the startup drive in order to back up the startup drive.
daBee33
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Canada
Post
Replies
Boosts
Views
Activity
Low swap space on primary drive has VM issues, so it closes apps apparently.