1. Install Unity 3.5.1f2 (http://www.unity3d.com/unity/download/) 2. Copy Unity.exe to your install dir\Editor\ (C:\Program Files\Unity\Editor\) (overwrite) 3. Start Unity and Select Manual Activation Click on Read License and point to the one supplied (Unity3d_v3.5.1f2_win_license.ilf) 4. That's