User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2 Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2 If you enter private browsing mode, then close all windows, you can't exit private browsing mode. The "Private Browsing" option in the Tools menu does not have a check mark, and selecting it does noting. In order to exit, you have to open a window, then the check mark appears and selecting it exits private browsing mode. Reproducible: Always Steps to Reproduce: 1. Enter Private Browsing mode 2. Close all windows 3. Try to exit Private Browsing mode
Could you try using ftp://ftp.mozilla.org/pub/firefox/nightly/latest-mozilla-1.9.1/? Beta 2 is pretty old.
Fixed in the nightly build.