I'm using Niresh 10.9 on VirtualBox, on Windows 7. It works fine except that whenever I shut down it ends up stuck at a pure gray screen that I then have to power off from. Anyway, I'm trying to update to 10.9.5 so I can install Xcode 6. But whenever I try to install OS X Update Combined 10.9.5, first the VM restarts, says Installing Software Update, then freezes (and VirtualBox crashes) at about 8 minutes left, every time. Is there anything I can do to fix it, and get 10.9.4 or 10.9.5 working?