Not sure if this will help anybody, but I had the 'second' issue, Unity 3D not loading so I fallback to Unity 2D.
I have an Intel i5 with Nvidia GeForce Optimus 420m.
What oddly worked for me was reinstalling 12.04. During the install process the second time around, I did not check the boxes to install proprietary software or download updates.
For some reason, installing it that way made Unity work for me. I've seen installed all updates, and still am running fine.
Not sure if this will help anybody, but I had the 'second' issue, Unity 3D not loading so I fallback to Unity 2D.
I have an Intel i5 with Nvidia GeForce Optimus 420m.
What oddly worked for me was reinstalling 12.04. During the install process the second time around, I did not check the boxes to install proprietary software or download updates.
For some reason, installing it that way made Unity work for me. I've seen installed all updates, and still am running fine.