I looked at macFixit (thanks, David), and did all the right things, and still Safari blew away. Turned out that it was the shareware Pith Helmet (the ad blocker). Pith Helmet had just upgraded to v 2.3.1 (see below), and then Safari 1.3 came out, and there were conflicts (that's why it blew away, I guess), so the author dumbed it back down with v 2.4 until he could work out the conflicts. Anyway, Safari is now back in action for me with the 2.4 version of Pith Helmet. Here's the info from his page: http://culater.net/software/PithHelmet/PithHelmet.php 0.1 What's New in v2.4 Support for Safari 1.3 has been added. Unfortunately, there are many interactions with this new version of Safari. I believe these interactions are bugs in WebCore/JavascriptCore and I will try to isolate them and report bugs to Apple as necessary. In the meantime, the content collapsing feature is turned off by default to keep Safari stable. 0.2 What's New in v2.3.1 This release is long overdue. It fixes a few minor issues that should improve PithHelmet's behavior and make it more usable. There are a few crash bugs and "hang" issues that have been resolved (mostly related to Java-enabled web sites). I also fixed a freeze related to streaming media (QuickTime streams). New countermeasures for popunder ads have been deployed. These are fairly aggressive, so I have shipped them turned off for the time being. They are the kind of thing that will likely wreak havoc on banking and other service sites / intranets that make heavy use of Javascript. There are new options in the "Ad Blocking" tab in the rule editor that should help get you sorted. As a treat for the web designers, I've added in a Javascript console that will allow you to run a script in the context of the current web page and interactively tinker and inspect the results. Nothing too sophisticated, but it seemed useful to me when wacking the popunders. 1.1 What It Does PithHelmet is an extended site preferences and ad blocking plugin for Apple's Safari browser. The basic purpose of the plugin is to empower you the user to view the web as you like. You can block ad images, Flash, Shockwave or horrible midi loops - the world is your oyster. This is just a series of hacks on top of Apple's WebKit framework, but it seems to work rather effectively. Due to the manner in which PithHelmet blocks ad content, most types of advertising content can be caught in the filter - this includes images, javascript, css, text, iframes, popups and popunders.