User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0 When I tried to open .mht web archive file in Firefox, it displayed no content and just kept opening new blank tabs. It was possible to close Firefox in a regular way while this was happening, so it did't freeze the program. Reproducible: Always Steps to Reproduce: 1. Open a webpage in IE (used IE 6 for this, tried several webpages) 2. Save as "Web Archive, single file" 3. Try to open it with Firefox The same when I saved a Powerpoint 2003 presentation as .mht Actual Results: Many open blank tabs and new ones popping up, quite funny to look at. Expected Results: File open in one tab, content visible. I installed Firefox 3 just today. Default theme. Some plugins/addons from previous Firefox2 installation, but nothing unusual.