Hi! (I couldn't find an Snow Leopard subforum, so I'm posting this here) I'm keeping one of my Macs at 10.6.8 (the rest of them are updated). It's a late 2010 Macbook Air. I'm facing an issue which began happening some months ago, and it's getting more frequent: When navigating some sites with Safari, the screen becomes totally garbaged (colors suddenly change, everything broken, the UI stops responding, the only thing that works is the mouse pointer but you cannot click anywhere), and then the only fix is a reboot. After a reboot everything is fine again. By inspecting the system logs, I traced the problem to be caused by Perian being called from the QuickTime plugin in Safari. In fact, going later to the same site with Firefox (which isn't affected by this issue) confirms there's a video ad in the site. My guess is some sites / ad providers are starting to use some video format that makes Perian crash so hardly that the whole OS X user interface crashes with it. Do you have any ideas on how could I workaround this? Firefox works without this problem, as I said, but I'd like to keep Safari usable on this machine (it's very usable indeed, but the risk of getting an OS X crash it's unacceptable). I could uninstall Perian, yes, but then the standalone Quicktime player wouldn't be able to play a lot of videos. I googled for ways of disabling Quicktime on Safari (not seeing videos on Safari would be much more acceptable than the risk of crashing OS X), but it seems it cannot be done on Snow Leopard. Any suggestions?