My enrollment appointment ends on July 4th at 8:00 AM. But it also says that open enrollment starts on july 4 and ends on september 13. Does that mean I can still make enrollment changes or add classes to my schedule after july 4?

Hi there!

Your enrollments appointment has probably already started, you can keep enrolling (i.e. adding/dropping)
in classes until the last date to enrol in classes which I think is Sept 13 (you can check sessional dates for McMaster in google).
"Open enrollments" just means that enrollment for classes is open to everyone. That is why the enrollment appointments are given out to make sure each respective year can enroll in their classes before enrollment is left open to everyone.

Lol I know I said the word enrollment way too many times, I hope you get the gist of what I'm saying.

Good luck!