Firefox does not keep older sessions, only your immediately previous session. There is an extension named Session Manager that can do that, but of course, it is not retroactive.

If Windows created a Restore Point recently, you might be able to roll back the session data file. Here's how to check on that possibility:

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

Help > Troubleshooting Information > "Show Folder" button

Scroll down to the files whose names start with sessionstore. You should find at least sessionstore.js and sessionstore.bak. If the .js extension does not appear on sessionstore, you should turn off the Windows feature that hides file extensions from you, so that you can work with file names as accurately as possible. This Microsoft support article has the steps: http://support.microsoft.com/kb/865219.

Leaving that window open, switch back to Firefox and Exit

Pause while Firefox finishes its cleanup, then make backup copies of all the sessionstore files to somewhere like your Documents folder for possible later restoration.

Right-click sessionstore.js > Properties > Previous Versions. This may take a while to load. Any earlier files look promising?

there are no previous versions available for sessionstore.js

Are there any previous versions for sessionstore.bak?

Are there any other sessionstore files (e.g., created at your last Firefox update)?

You seem to have the Session Manager extension installed.

Did you had this extension before to handle multiple sessions?

yes I have recovered about 20 of them using recuva software but after I click them there is just a bunch of characters

the session manager came after this

Hi aa352040, when you say, there is just a bunch of characters, does it look like garbage data, not like a "real" sessionstore.js file? In that case, it seems you are out of luck with a regular restore. You may need to use your history to reconstruct what you had open during that session.

yes they are characters, but I am looking and they do contain the website urls which I was at last, if that makes any difference

You can try to start Firefox with that recovered file. Back up your current sessionstore.js/bak files as described earlier, then replace sessionstore.js with one of your recovered files, rename it to sessionstore.js, and start Firefox. Can it read the file? Any of them?

These threads list techniques for "mining" an old sessionstore file to extract the URLs. They might work with a recovered file, depending on the degree of damage.

• Using Firefox's Browser Console (formerly known as Error Console): https://support.mozilla.org/en-US/questions/969046#answer-471950

• Using Firefox developer tool "Scratchpad": http://forums.mozillazine.org/viewtopic.php?f=38&t=622036&start=60&p=12098147#p12098147 (this is the one you already tried)

• Using a third party website: https://firefox-session-restore.herokuapp.com/

If the files are less than 1MB then you can try to validate the JSON files online.

• JSON Formatter & Validator: http://jsonformatter.curiousconcept.com/
• JSONLint - The JSON Validator: http://jsonlint.com/