This error happens immediately following the first underwater test. I am not running any other applications and I'm not moving the mouse or doing anything else during the test. I tried both centered and stretched, yet it does exactly the same thing either way. I'm puzzled because the previous version worked perfectly but nothing physically has changed. The ONLY thing that has changed is my monitor, I went from a 1080 to a 1200. Its weird because the entire first test completes, and then it gives the fullscreen error. Any insight would be great, otherwise, no big loss. I got the 3dmark11 for free with my evga 580's so it was just a bonus. Thanks for your time.
Just to rule out some things, since you appear to have Advanced Edition, could you try running the benchmark in Windowed Mode and see what that does (yes, that makes it a custom run so it isn't a solution, just interested in narrowing down potential causes)
I tried it this morning, and in "windowed-mode" it worked just fine. My driver for the gpu's is the latest whql nVidia driver 285.62
As I was writing this, the whole window mode thing made me think. I have a high-end HP monitor, and part of the driver package is the ability to rotate and partition the screen. So, I exited the application and 3dMark11 works fine. I don't know why it allowed the first test and it interfered with the second, but it doesn't matter. Problem solved. Thanks for the help and sorry for the trouble.
Glad you got it solved. I believe the issue here is that the application that does that auto-rotate is not fully working with fullscreen DX11 applications and when, between tests, the screen switches back to desktop for a second (before loading screen comes up), the software does something that causes 3DMark 11 to lose focus and that pops up the error when test 2 starts.
(Reason for the error is that 3DMark 11 must not lose focus during testing or the benchmark result would not be valid - it is part "anti cheat", part ensuring that the score is not influenced by outside factors. Windowed mode is a custom benchmark mode so there it isn't a factor and the test doesn't get tripped up by the strict validation)
...and that's why any background applications that might interfere with screen rendering (like the on you had running) should be closed for the duration of the benchmark.