Step 1: Rescue any sessionstore files in your profile folder. Do not exit Firefox first.

Open your current Firefox settings (AKA Firefox profile) folder using either:

• "3-bar" menu button > "?" button > Troubleshooting information
• Help menu > Troubleshooting Information

In the first table on the page, click the "Show Folder" button

In the window that opens, scroll down and copy all sessionstore files to a safe location such as your Documents folder. These should include:

• sessionstore.js (current windows/tabs)
• sessionstore.bak (previous session windows/tab)
• sessionstore.bak-datetime (windows/tabs at last update)

You may also find:

• sessionstore-1.js and other numbered files

Those can indicate that sessionstore.js is corrupted to locked and needs to be replaced. If you find one of those the most recent one may contain your last session. Let's discuss what to do in that case.

I'm sorry to hear that you have had this problem repeatedly. Obviously it is very frustrating.

It is interesting that if you use Exit (normally), you can restore your session fine at the next startup, but in any crash scenario, you have to start from scratch? That's definitely not the way it's supposed to work; the origin of this feature was crash recovery.

Could you use the about:config preferences editor to see whether you have any non-default settings for session history? Here's how:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box that appears above the list, type or paste sess and pause while the list is filtered

(3) Scan down through the preferences whose names start with browser.sessionstore. for any that are bolded and indicate they are "user set" or which are italic / locked. You can right-click > Copy and paste them into a reply to see whether they are relevant to this problem.

(Please note that using private windows, automatically stating in private mode, or clearing all history at shutdown will bypass/delete normal session history.)

Meanwhile, you might benefit from using the Session Manager extension. It allows you to save multiple sessions so that if the latest one is unusable, you have the option to try a previous one. It also can save backups outside your regular settings (profile) folder in case either Firefox or external software is clearing history from that folder. More information: https://addons.mozilla.org/firefox/addon/session-manager/

Also, as an emergency measure, consider using the Bookmark All Tabs feature when you have accumulated a number of important tabs in a window. That command is available from the following places:

• right-click any tab in the window
• Ctrl+Shift+d
• Bookmarks menu if accessed using Alt+b

Only one is:

browser.sessionstore.upgradeBackup.latestBuildID;20140605174243

All the rest with "browser.sessionstore" are set to Default

I've re-installed a number of times and have installed Session Manager but it has two problems:

- Does not AUTOMATICALLY save - Each Saved session doesn't save all the tabs - Program itself is FULL of bugs and VERY Unreliable. There is a HUGE thread on people having issues with it.

It didn't work for version 29 and still doesn't for 30.

Settings sound okay.

Was there anything usual when you backed up the sessionstore.* files?

Do you use Advanced SystemCare (Surfing Protection) or any other utility/security programs with features that might roll back or clean out settings files?

Do you start/run Firefox in any special way, such as using sandboxing software?