unity won't start

I downloaded the newest Unity and when I went to click on the “install” button it didn’t work. My system is a Macbook running on 10.5.8 from 2007. I have to have at least 10.4 for unity to work and it won’t…what gives?

Basically, when I click the install button on the game it won’t do anything, it sometimes makes my dashboard crash when I click install. I don’t know how else to describe the problem! Sorry!

did you try reinstalling it this is not so common error but reinstalling helps