An instructor can make a course invisible to students while they are editing it. This is accomplished by setting the Active flag under the Course Offering Information screen. All courses are delivered with this setting as active.
Steps to changed the active status.
1. From the course's My Tools menu select Course Admin
2. From the Course Administration screen select "Course Offering Information"
3. Find the "Active" section to set the value. Checked = Visible; Unchecked = Invisible
4. Save your changes.