Hello, I have an annoying issue on my Mac Mini (i7 2011). When I leave it alone for a longer period of time (sometimes hours, sometimes one/two days) and then I log in again I just realize that the mac forced a reboot on its own. Sometimes I can avoid this since a window from an application blocked the restart thus leaving me with the possibility of getting access to my previous session. This is very bad, expecially when I have to leave my desk for something urgent and I expect to continue my work as soon as I am back. The funny thing is that it does it not just in yosemite, but also with previous versions of the OS. It clearly seems to be a software thing - since sometimes I catch it while it is trying to do it and I see no kernel panic or stuff like that - any idea how to solve it?