Hi, Last night i turnt on my MacBook as usual, used it for a bit then got a message from Little Snitch to say there was an update available, and asked me if i would like to update. I did, and followed the installation until it said a system restart was required to finish the installation. So i clicked restart. Now my mac shows the usual loading screen but with a loading bar, for about 15-20 seconds, it doesn't fill the whole way. Then it shows the normal grey loading screen thing with just the apple logo and spinning gear thing. But won't go past this. How can i fix this. I have tried holding shift to go into safe mode, this doesn't work. Need a fix asap as i'm meant to be travelling on tuesday coming with it! HELP PLEASE!!!