Firefox crashed only restored half my tabs

For Firefox 32 and earlier:

Sorry to hear about this problem.

To preserve as much of your session history as possible, please DO NOT CLOSE Firefox.

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

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

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

In the window that launches, scroll down and save a copy of all files whose names start with sessionstore to a safe location, such as your Documents folder. We may be able to use them to recover your blank tabs.

The kinds of files you may find in your new backup of sessionstore files includes:

• sessionstore.js: the windows and tabs in your currently live Firefox session (or, if Firefox is closed, your last session)
• sessionstore.bak: the windows and tabs in your last Firefox session
• sessionstore.bak-datetime: the windows and tabs in the Firefox session that was live at the time of your last update
• sessionstore-1.js (or other numbered files): windows and tabs saved at a time when Firefox was unable to update the sessionstore.js file

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing windows and tabs?

Whoops, these files moved and got new names in Firefox 33... here's a new version of my previous post:

Please back up your session history files to a safe location for potential recovery/salvage operations.

You can open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

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

In the window that launches, scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs.

The kinds of files you may find among your sessionstore files are:

• recovery.js: the windows and tabs in your currently live Firefox session (or, if Firefox is closed, your last session)
• recovery.bak: a backup copy of recovery.js
• previous.js: the windows and tabs in your last Firefox session
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

You might also find files Firefox created if it could not update recovery.js (but since Firefox 33 is so new, I don't know what they would be named).

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing tabs?

Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mentioned, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions