Courses cannot be deleted if they have been offered.  The Course must be unoffered before it can be deleted.

To unoffer a Course:
  1. Go to onCampus > Procedure > Academics > Offer Course
  2. Expand the appropriate Department and unmark Offer for the CourseUser-added image
Why can't I unoffer the Course?

To delete the Course once it is unoffered:
  1. Go to Core > School > Departments & Course
  2. Expand the appropriate Department and click the red 'X' to delete the Course