If you haven't closed your browser, usually you can use

History > Restore Previous Session

or the button on the built-in Firefox home page (about:home).

However, that doesn't always work; session restore isn't 100% reliable.

Are you still running Firefox 17? For security reasons, you should update to Firefox 19. You can use the "Check for Updates" button here to do that:

Help menu > About Firefox

If you have a specific reason that you feel you can't update, what is it? Maybe there's a good workaround.

Yes, there might be a way to restore your tabs. I can't answer this for every version of Firefox, now. So, please write me the version you are currently using and I am going to help you tomorrow. ;-)

If you are still using the current version of Firefox, you may choose this way: "Firefox" (Button, left side top) -> "History" -> "Restore Previous Session"

Thank you both for your response, but you will note I restarted the computer. This will naturally have closed Firefox in the process. I then started Firefox and opened a new tab. Restore previous tabs option is not available. Using Firefox 17.04

Normally when you restart Firefox, the option to restore the previous session will be present, regardless of how you shut down Firefox. But... no guarantees and at this point it might just be gone.

If you open your currently active Firefox settings folder (AKA your Firefox profile folder), you might find a file named sessionstore.bak with a promising timestamp. If you think it dates from your lost session, make a copy of that file in a safe place and we can try to substitute it back as your session history file.

To open your profile folder:

Help menu > Troubleshooting Information > "Show Folder" button

Make your copy for safekeeping. Exit Firefox. Once Firefox has finished updating the files in the folder, rename sessionstore.js to sessionstore.old and copy your sessionstore.bak back and rename it to sessionstore.js.

Restart Firefox, then restore your previous session using the History menu. Any luck?

jsher2000 - Thank you so much for your helpful advice. I tried it and I think it would have worked fine except that having realised originally that I was in the process of opening a new tab prior to restoring the previous ones, I think I closed Firefox to try to stop the new web site loading, and in the process it must have overwritten sessionstore.bak. Had I not done that I think your solution would have worked a treat. I will save your advice in case a similar thing happens again. Thank you.

You can try to restore a previous version of the sessionstore.js or sessionstore.bak file. You need to rename the .bak file to .js to make Firefox see that session.

• right-click: Properties > Previous Versions

• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

• http://kb.mozillazine.org/sessionstore.js
• http://kb.mozillazine.org/Session_Restore

• https://support.mozilla.org/kb/restore-previous-session

cor-el - Thank you so much. I found a previous version of the .bak file that had all 29 tabs saved. Restoring it saved me an immense amount of time and frustration. You deserve a medal.

You're welcome.

HI all, i have the same problem also! I saw there is a sessionstore.bak and sessionstore.js file on firefox, am i suppose to change .bak to JS? i tried that but it was name sessionstore(2).js instead. If i am to open restore previous session, should i do that in sessionsotre.js or sessionstore(2).js? (i tried doing that in sessionstore.js by clicking restore previous session but still it didn't work.) Please help!

Hi cyl90089, copy all your sessionstore files to another folder in case things go wrong. When renaming files, make sure Firefox is closed. Next time it starts, it should look for sessionstore.js, not the numbered file. If that .bak file that you renamed didn't contain what you want, then try the recovery.

Thank you for your help Jscher. I am not a technical person so i need a step by step guide. Can you help me with that? So step one is backing up the file, step 2 is rename bak to js? what is the third step? thanks so much in advance!

Hi cyl90089, I think between your latest reply and my earlier long post, you've got almost all the steps. The last thing is to start Firefox and restore the previous session (e.g., from the History menu).

Thanks! I understood your earlier post up to this point: Make your copy for safekeeping. Exit Firefox. Once Firefox has finished updating the files in the folder, rename sessionstore.js to sessionstore.old and copy your sessionstore.bak back and rename it to sessionstore.js.

Once firefox has finished updating. So do i assume the firefox will update automatically once i copied the file and exited?

Hi cyl90089, you wrote:

Thanks! I understood your earlier post up to this point: Make your copy for safekeeping. Exit Firefox. Once Firefox has finished updating the files in the folder, rename sessionstore.js to sessionstore.old and copy your sessionstore.bak back and rename it to sessionstore.js.

Once firefox has finished updating. So do i assume the firefox will update automatically once i copied the file and exited?

What I meant was this: Somewhere between 5 and 20 seconds after closing Firefox, a bunch of the files in your profile folder get updated. You can see the timestamps change if you have Windows Explorer set to show the "Details" view. After that, it's safe to do the copy/rename procedures.

The reply locate folder, backup sessionstore.bak then use it to replace sessionstore.js worked ok but the .bak file was not the session I wanted.

I used this: To open your profile folder: Help menu > Troubleshooting Information > "Show Folder" button There is a session folder under that open it, choose the session you want to recover, double click it, tell windows to use firefox to open it, Firefox opens as far as the session select window, select your choice job done.

I am running firefox V21.0 win XP pro on a Dell D830 Laptop.

Hi davidnrn12, Firefox only stores one session. If you need to go back further, unfortunately that isn't possible without an add-on. Both of these extend the session restore feature and might be worth a look if you anticipate having this requirement in the future:

• https://addons.mozilla.org/en-US/firefox/addon/session-manager/
• https://addons.mozilla.org/en-us/firefox/addon/tab-mix-plus/

Hi "Firefox only stores one session." Not true in my case guess it is because I am running Session Mgr 0.8.0.7 Been there so long thought it was part of Firefox. Attached sreenshot of my session folder.

Screw Firefox if it makes it too complicated to live. I'm switching to another browser. How many times I lost History => Restore Previous Session tabs with important info. Digging into History is too time consuming. I'm not a gamer! Don;t have time to waste. Thus I'm quitting FF and using Chrome and IE again, after many years. Bye-bye FF and bye-bye unreliable tab saving.