XP / VISTA USERS
Go to the Start Menu and click Run. Type in %appdata%.
Then click 2K Sports, then NBA 2K12. Here you will find a folder called Saves; this is where you need to extract the .ROS file included in this archive.
WINDOWS 7
Type %appdata% in your Start Menu's search bar and press Enter.
It will take you to your Roaming folder, where you can click 2K Sports and then NBA 2K12. Extract .ROS to theSaves folder.
I only adjust the roster from the 2k sports NBA 2K12 Official Roster Update 28/04
Released center Jermaine O'neal for the Celtics and released forward Bill Walker for the Knicks and signed center Dan Gadzuric. Wait for the next Roster Update. Enjoy playing NBA 2k12.. :D