first go to ur Games section then go to Game Data Utility then delete Rainbow 6 vegas 2 then when it asks u to download the patch press O and it will skip then
ur back in business. DONT DELETE UR RAINBOW VEGAS 2 FILE FROM SAVED DATA UTILITY DELETE IT FROM THE GAME DATA UTILITY SECTION

if u want to play online u have to update the patch and it wont work follow this steps again it it will work again

Thats it

Enjoy