User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6 I often have three browser windows with several tabs and Firefox/SessionManager usually fails to load the complete session. Two windows are loaded correctly, but the window in the middle of the Windows task bar is completely empty (white). It does not even show the menu bar. I guess, there is some kind of deadlock situation. First, I thought it might be the session manager plug-in, then I discovered that session restore works sometimes if I disable the HTML validator plug-in. However, after further testing, this issue does not seem to be related to the two plug-ins at all as the deadlock(?) situation can be reproduced by even deactivating both plug-ins. Reproducible: Sometimes Steps to Reproduce: 1. Set the start-up option to "Show my windows and tabs from last time" 2. Open three browser windows, go to the http://www.apache.org/ website and open the projects from "HTTP server" to "Directory" in separate tabs of the first window, from "Excalibur" to "Labs" in separate tabs in the second window, and from "Lenya" to "Perl" in separate tabs of the third window. 3. Close Firefox and restart Actual Results: After startup, one window is blank (interestingly, in my case it was always the one with the projects from "Excalibur" to "Labs") and does not even show the menu bar. If the session is restored correctly, repeat step 3 of above. Expected Results: After startup, all windows should be restored correctly.

I'm not able to reproduce this behavior at all after half a dozen restarts. Does the same issue happen on a clean profile as well (see <http://kb.mozillazine.org/Profile_manager> for how to create one)? BTW: What are your computer's specs (mainly CPU and RAM)?

The issue does not appear with a clean profile. However after some further testing, it seems to be the SwitchProxy add-on that is causing this behaviour. I could reproduce the the issue with a clean profile, installed SwitchProxy, and performing the steps described in the initial comment. Session restoration almost predictably fails at the second Firefox restart. My old profile with deactivated SwitchProxy now correctly restores the sessions. Notebook: 1GB RAM, 2GHz Centrino

Thanks for the debugging help! Please inform the SwitchProxy author(s) to investigate what they might be doing something wrong and have them file a new bug against SessionStore should they suspect that this is still our bug (including minimally required code to reproduce the issue). -> WORKSFORME (extension incompatibility)