I recently updated Thunderbird to version 1.5.0.9. After the next reboot, my e-mail monitor PopTray 3.2 and my Thunderbird e-mail client both timed out whenever they tried to read mail from my ISP’s server. For the next four days I had only sporadic access to e-mail: typically, I could send a test message and clear things up, although this did not always work, and the problem always recurred after the next boot. Great nuisance! So great that I finally resuscitated my Outlook Express e-mail client and found that it also timed out in the same way.
I finally found that the problem is definitely connected with Comodo Firewall (2.3.6.81 currently) and, in fact, that I could eliminate the problem by simply reverting the Components Monitor from ON to LEARN.
I suppose that the Thunderbird update mangled some library or other and the mode change circumvented this. In any event, I am working again, although I would prefer to have Component Monitoring ON.