From the Calendar:
"All graduate students admitted to the Faculty of Graduate Studies must register when they begin their studies. Students must remain continuously registered until the degree is completed, except for periods of time for which the student is away on an approved leave of absence*. Failure to register for two consecutive terms may result in the student being required to withdraw.
"Students must only register in courses that are part of their graduate programs. If students do register in courses unrelated to their grad programs, they are still responsible for completing the courses with the required minimum grades for graduate students, or must re-take or make up the course. Graduate students cannot graduate with unresolved failing marks."
Note: Continuous registration includes the summer term.
*Exception: Students in master's programs that are delivered entirely online, and who pay fees per course or per credit, are not eligible for leaves of absence. They can take time away from their studies by not registering in courses. The five-year maximum time in program still applies.