After upgrading, my screen resolution (added by xrandr comands on the start) did not work like before. Messages appear showing some errors (that i have never had in 11.10). "No se pudo aplicar la configuración almacenada para los monitores"/"Can't apply the stored configuration for the monitors." This script didn't work either.

xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync xrandr --addmode VGA1 1280x1024_60.00 xrandr --output VGA1 --mode 1280x1024_60.00

I also tryed deleting monitors.xml but, nothing. This only erase the window message.

It's been sayd that ##It's a normal buggy and well know problem for Pc's with Intel integrated video cards.##

The new version of gnome-settings-daemon stores its configuration information in dconf rather than gconf.

I tryed something, but the problem persist. This is what i did.

Install the dconf-tools package, and then run dconf-editor. In the tree on the left, navigate org -> gnome -> settings-daemon -> plugins -> xrandr. Uncheck the active checkbox. restart your XServer (Ctrl+Alt+Backspace) (It didn't worked out for me, but it may be helpful to someone)