I love Unity 4.0, but I want to download Unity 3.5.6f4 again because I had Android exporting on that version.

Also is it a bad idea to have two versions of Unity Installed on your PC?

So what if he missed it?

Here is the link for the PC version: http://download.unity3d.com/download_unity/UnitySetup-3.5.6.exe

Here is the link for the MAC version:
http://download.unity3d.com/download_unity/unity-3.5.6.dmg

So, you came to Unity Answers to get help, and somehow managed to miss:

When I type “Download link for previous versions of unity3d” into a new question Answers prompts me with a number of related questions…