Hi, Mavericks performed an unscheduled update on my machine last night which resulted in the grey screen of death. I booted in safe mode (and got the lovely message that the Mavericks update had been successfully installed) but got the flashing grey screen / background with no dock. I've since rebooted to the same result. Unfortunately most of the advice regarding this issue involves making use of the Activity Monitor or Finder, neither of which will open (I will continually get the "[item] closed unexpectedly, do you want to reopen" message when I try). I've also tried rebooting with CMD+R held down (with the lofty ideal of re-installing Snow Leopard (that being my OS before Mavericks (which I've not been happy with at all)), but attempting to do so leaves the machine hanging with the apple logo on screen. I don't live particularly close to an Apple Store, so won't be able to go for a couple of weeks (and given the unscheduled nature of the update that caused this, I'm baulking slightly at the idea, if I'm honest). Any advice gratefully received. Thanks in advance.