Last day for cancelling courses without failure by default for Term 1 courses is Wednesday, June 4. For Term 3 courses it's Wednesday, July 23. The last day to drop courses and receive a refund was Friday, May 9.
For Term 2 the last day to register/drop is Friday, June 27. To cancel Term 2 courses without failure by default is Wednesday, July 23.
http://registrar-old.mcmaster.ca/CAL...ent/pg195.html
You can find this information in the future by looking up "McMaster sessional dates."