I've just downloaded Unity, I have got a problem during lauching it, which crash just after choosing the project. Before crashing Unity propose to change file permission on project directory.
However everybody can read write and execute on the project directory, I set it manually.
I'm not alone to have this problem : http://answers.unity3d.com/questions/1618/unity-crashes-after-setting-project-permissions
I work with a macbook pro with snow leopard, using case sensitive file system.
Could you help me.