Internal compiler error!

Internal compiler error! the path is:D:\cg\unity\Editor\Data\MonoCompiler.framework\gmcs, cannot open it ! The problem appears at once when I open the Unity ,what should I do,I am a new.And the Unity I have is a free vision. I wish what I describe is very clear.

This is 99% certain caused by the chinese characters in your path. Try installing Unity in a path without chinese characters, and see if that solves the problem.