I posted this on the Apple Discussion thread but had no luck with what the issue might be so i thought i would see if anyone on here might know what the issue is as they have helped me out in the past. Im not 100% sure when it started but im pretty sure it was around the time of the 10.7.4 update, so within the last 4 weeks. So before i go into the issue here are the specs of the machine i am using: MacBook Pro 15-Inch, Mid 2009 Processor 2.8 GHz Intel Core 2 Duo Memory 4 GB 1067 MHz DDR3 Graphics NVIDIA GeForce 9600M GT 512 MB Software Mac OS X Lion 10.7.4 (11E53) The issue: When i connect my external monitor (LG Flatron M227WDP) via the VGA to MiniDVI to my MacBook Pro i get lines going accross my screen and giving the impression of the screen tearing, i think i might have seen this on my MacBook monitor as well but im not sure if that was just my eyes playing tricks on me (although i have noticed a different issue, a checkerboard effect appears over my Minecraft game from time to time, a lot like the effect over my other external displays when i connect them to my Macbook) Since the issue is hard to discribe i did my best at taking a video of the problem to make it a little clearer.... http://www.youtube.com/watch?v=aK2BaOIp0a0 I used the Wikipedia site as a background as it has an image, text and white space in hope to pick up a stronger image of the problem. as you can see there is a lot of lines coming from the left most of the screen and effecting not only the sides but the middle of the screen as well, i've not noticed any on the right hand side. I have replace the VGA cable twice and i have sent off my monitor to PCWorld where i purchaced it but they where unable to find a probem with it, i have requested they take it back again for more tests as the issue is still there but after a 5 hour test they have found nothing wrong with it so the only thing i can think of is that its the MacBook Pro but i have search many forums and not found anything of this issue anywhere so thought i would ask on here in hope that someone might know what is wrong. I have noticed that it happens intermitently and can last anywhere between 30 seconds and 3 minutes, but then after a rest period it happens again, to induce it i was playing Minecraft which gave me the video above but after closing all that i noticed that it was still happening while i was exporing the video and also while i was writing this post (although not as extreme as the other 2). I hope that this is enough information for someone to work out what the problem is but if not i am happy to give more. I have also used my AppleCare TechTool Deluxe which found no issues with any of the critiria of the Mac if that is of help also. I thank you in advance for any replies. I have AppleCare so i could pop over to the AppleStore but my closest one is a £15 train ticket and i'd rather know that its not just a software issue before spending that.