How do I install and switch to the Unity 2D desktop?

For 11.10, 12.04, & 12.10

Users of 11.10 and above have Unity 2D installed by default already.

To use it, logout, you will be confronted by the LightDM manager.

Then, click the little cog wheel, and select Ubuntu 2D.

Then, enter your password, hit Enter and you'll be logged into Unity 2D.

For 13.04, no need to do this - they have integrated the Unity 2D and Unity 3D environments.

For 10.10

For people running 10.10 you can add the Unity 2D PPA.

Go to Applications -> Ubuntu Software Center -> Edit (Menu) -> Software Sources -> Other Software (tab) -> Add and then paste ppa:unity-2d-team/unity-2d-daily and then install unity-2d from the software center.

This will install all of the necessary dependencies to run Unity 2D, including a "Unity 2D" session that you'll need to login with. Then log out and when logging back in select "Unity 2D" at the bottom of the login screen.

_{(source: xrmb2.net)}

Command Line Instructions

sudo add-apt-repository ppa:unity-2d-team/unity-2d-daily
sudo apt-get update
sudo apt-get install unity-2d

• What are PPAs and how do I use them?

For 11.04

Users of 11.04 can install unity-2d from the archive.

This will install all of the necessary dependencies to run Unity 2D, including a "Unity 2D" session that you'll need to login with. Then log out and when logging back in select "Unity 2D" at the bottom of the login screen.

_{(source: xrmb2.net)}

Command Line Instructions

sudo apt-get install unity-2d

For 13.04 and onwards

According to Ubuntu Forums:

Unity 2D was removed from 12.10 onwards. We now have something called llvmpipe which has the purpose of providing Unity 3D on lower specified PCs.

I don't think there will be interest in resurrecting 2D development.

I know this is not a direct answer to the question posted, but it rather leaves you with two possible choices (if you seriously need Unity 2D):

1. Reinstall and stick with 12.04 (currently 12.04.2).
2. Use the "fallback" session in either 12.10 or 13.04.