Hopefully this is in the right section. My dad works as a teacher and his MacBook Pro has been freezing lately after he disconnects the second display, which is a projector (through the vga adapter). This is annoying because the computer locks up and he has to force reboot it to fix it. I've looked on Google and I can't find any relevant information on this issue, I tried resetting the NVram but the school seems to have put some lock on the computer that prevents you from changing sensitive parts of the computer (like resetting admin passwords etc...). I also saw that pressing command + F1 before disconnecting the cable works for some people but I haven't had a chance to test it yet. Does anyone have any information on this?