SD fails - "Unable to copy extended attributes from directory /private/mnt"

[JoBoy]

When something is trying to "call home," Little Snitch alerts you. You have the option of denying permission until the present application quits or denying permission "permanently." When you deny permanently, Little Snitch will not launch a window that interferes with the backup. When you run SD! the next time, no window will open to interfere with the backup.

In this case, "permanent" doesn't really mean forever. You can open Little Snitch and easily find the permanent rule that you created and delete the rule if, later, you should discover a need to do so.