Installing Multiple Versions of Unity

You can install more than one version of Unity on your machine as long as you follow the correct naming conventions for your folders. You need to rename each of the Unity folders themselves, so that the hierarchy looks like:

Unity_3.4.0
---Editor
---MonoDevelop
Unity_4.0b7
---Editor
---MonoDevelop

PC

• Install Unity 4.0 (www.unity3d.com/download)
• When you install on PC it will select the previously installed directory - do not install here
• Create a new directory named sensibly e.g. “Unity_4”
• Name any shortcuts so you know which version you are launching
• Hold Alt when you launch the editor to force Unity to let you choose which project to open (otherwise it will try and upgrade the last opened project)
• Choose your projectname_4 directory to open your backed up project

Do not rename each Editor folder inside a single Unity folder! You will overwrite the MonoDevelop folder and this will cause serious stability problems and unexpected crashes.

Mac

The installer for Mac will always install Unity into a folder called /Applications/Unity. This will overwrite any previous install in that folder. On the Mac the folder name can be changed without it affecting Unity provided Unity is not running.

• Find your existing Unity application folder and rename appropriately e.g /Applications/Unity350.
• Install Unity 4.x (downloaded from www.unity3d.com/download).
• Name any shortcuts so you know which version you are launching
• Hold Alt when you launch to force Unity to let you choose which project to open (otherwise Unity will load the last opened project and and upgrade it.)
• Choose your projectname_4 directory to open your backed up project