I have Ubuntu 13.04 Raring Ringtail (final release) installed on an USB 3.0 external hard drive. The goal is to be able to use it on any computer with a USB 3.0 port. I have successfuly installed the ati 13.4 graphics driver on it - this is for my desktop which has a Radeon HD 7950 graphics card. I also would like to use this Ubuntu on my Mac, with Intel HD 4000 integrated graphics. Ubuntu works on my desktop with the ati drivers as it has the ati graphics card, however gave me a "low graphics mode" warning; I selected the option "reset graphics" and restarted. Ubuntu starts (the login screen is normal) but Unity no longer stats and so I have no windows border, no sidebar or top menu. I can right click and it show menus and I can open the terminal with the hotkey for it, but nothing else.
Keep in mind: Ubuntu still works on the desktop with the ati graphics card, however it does not on my mac which had intel HD 4000 integrated graphics. Before it worked on both, but because of the lack of proprietary drivers, there was serious lag on the desktop.
Thank you for any help on how to get Unity to start on the mac!