Hi im starting mcmaster this fall and I haven't registered yet for my courses cause I was waiting for my acceptance to be final. Im aware that SOLAR is closed right now but when it opens tomorrow will I still be able to register?

yup i believe so, based on this.

"for those students who are newly admitted after July 16th"
I was pretty much in the same boat last year. The only this is, you have to make the timetable urself. Note that some class may be full, considering the fact that you are adding courses now.

Not enitrely sure if u can get in, but try any way. Contact the Office of the Registrar and let them know if it does't work.

Yes, but you're going to have a hard time getting your courses to fit together into a timetable. Most of the good courses and times are in high demand and will most likely be all filled up by now.
I heard that you could contact the course coordinators at the beginning of September if a mandatory course is full.

P.s. Even on Thursday, SOLAR will probably be too busy to let you on right away, because that's when pretty much the whole school logs on to change up their lab/tutorial times.

Good luck, though.

No, because SOLAR only opens up for students who have previously registered with fees cleared tomorrow. You won't be able to register until the day for "all other students", which is I believe the 14th?

And yeah, a lot of the good courses will be taken and sectioning will be a pain.
If SOLAR would have allowed you to register then you should have done so, whether or not your acceptance was final. Most incoming first years register before their acceptance is final anyways, since it's before final marks come in.