Hi, @Mariah_Rhino when Rhino fails to start, I assume you mean it installed fine, but sill not launch-
are you on a mac or a pc?
if on a mac, do you have enscape installed? if so see this thread-
if you are on a pc and are not using enscape, see this thread-
Let us know if either of those fixes do not work,
you are welcome to email us directly at tech@mcneel.com for a support ticket or call us as 206-545-6877