restore Firefox sessions

How to restore Firefox sessions if Session Restore is not working correctly
by Martin Brinkmann
Firefox saves two files with Session Restore information to the user profile:

• sessionstore.js contains information about the current session. If you monitor the file you will notice that its size increases and decreases during a browsing session.
• sessionstore.bak which contains session information from the previous session.

Tip: You should not re-open Firefox when Session Restore fails to load the previous session as you may end up overwriting the backup file as well. Since it contains information that have not been modified after a session fails to load, you should copy it to a secure location before you continue.

Restoring the Firefox session
Once you have backed up both session files, you can start to investigate the issue and try to restore the previous session.
First thing you may want to do is compare the size of the sessionstore.js and sessionstore.bak file. If either file has a size of 0, it is empty and not usable anymore.
With Firefox closed down completely, open one then the other file in a text editor of choice. It should display session information in text form. If you see corrupt text or no information at all, it is clear that the Session Restore file is corrupt and not usable anymore.
You can still try and extract web addresses from it if some information are still displayed in it. This may allow you to recover at least some websites that you had open previously.
Before you do so, try deleting the broken sessionrestore.js file and rename the sessionrestore.bak file to sessionrestore.js.
This attempts to restore the browsing session from the backup. Note that it does not include tabs, windows or forms that you have opened in your last session, and that it may include tabs, windows or form data that you have closed in the previous session.
Where the Session Restore files are stored

The browser stores the sessionrestore.js and sessionrestore.bak file in the user profile directory.

• Window XP and earlier: C:\Documents and Settings\\Application Data\Mozilla\Firefox\Profiles\
• Windows Vista and later: C:\Users\\AppData\Roaming\Mozilla\Firefox\Profiles\.
• Linux: ~/.mozilla/firefox/