Since the recent update from firefox2 to firefox3 the links in my mails do no longer work. No window pops up. After some debug I found the problem. Let's share it with others that experience the same problem: I'm using Thunderbird 2.0.0.17 (manually downloaded, that might have caused the problem, I have not tried with 1.5) I'm using Firefox 3.0.2 (yum installed CentOS 4.7) To solve I created a small wrapper script that unsets LD_LIBRARY_PATH: cat <path>/firefox_wrap #!/bin/bash unset LD_LIBRARY_PATH firefox $@ To start add : user_pref("network.protocol-handler.app.http", "<path>/firefox_wrap"); to ~/.thunderbird/<salt>/prefs.js (or use the advanced config editor) The error message (for those Googling around): /usr/lib/firefox-3.0.2/firefox-bin: /opt/thunderbird-2.0.0.17/libnss3.so: version `NSS_3.12' not found (requiredby /usr/lib/firefox-3.0.2/libxul.so) Cheers, Theo