I installed from iso. I rebooted once it was all good. I changed vbox take screenshot key to host(right ctrl) + f12. And tried to take screenshot. Bom! Suddenly the screen gone black. I figured it didnt changed. So i check out the setting but didnt find what is alt+f12 doing.
So i shutdown and tried to launch again. Its all brand new OS. Than i unplug the iso. Take vdi from Controller SATA to Controller IDE. And know only remember my user and 1920x1080 screen. No firefox history or installs nor dekstop files.