Do you mean restoring automatically or that also the entry in "History > Restore Previous Session" is grayed?

In case you are using "Clear history when Firefox closes":

• do not clear the Browsing History

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings
• https://support.mozilla.org/kb/Clear+Recent+History

Note that clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, and passwords.

restore the tabs automatically. Every time, not just for crashes. General > Startup > When Firefox Starts: Show my windows and tabs from last time no longer brings back the tabs and windows on restart ever since the update.

anyone?

Did you check the "Clear history when Firefox closes" setting?

Can you restore the previous session via 'History > Restore Previous Session"?

See also:

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

under privacy > history > firefox will: is set to remember history.

restore previous session is grayed out in the the history menu.

I didn't changed any settings. My tabs restored just fine on restart every time until the recent update to 21.0 and now it will not restore even though I have changed none of the settings.

You can check for problems with the sessionstore.js and sessionstore.bak files in the Firefox profile folder that store session data.

Delete the sessionstore.js file and possible sessionstore-##.js files with a number and sessionstore.bak in the Firefox profile folder.

• Help > Troubleshooting Information > Profile Directory: Show Folder
• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Multiple_profile_files_created

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them).

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder

If you use cleanup software like CCleaner then check the settings for the Firefox application.

I am also having this restore issue...and on my Firefox homepage there is NO button that says "Restore Previous Session", like it used to have......HELP....when my session crashes I lose all my tabs and tab groups....how can I fix this?? I have all the correct settings so under normal circumstances all of them open, but when the session crashes...I lose them all and can NOT restore!

Did you make sure that Session Restore is enabled?

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

I can not find a place to do that...I have looked everywhere in the Option menu.....where should I find it???

You can check the sessionstore pref on the about:config page and reset Boolean refs that are user set (bold) via the right-click context menu.

Did you try to delete the sessionstore.* files in the Firefox profile folder?

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

it is working now all of a sudden.... I don't get why it would randomly stop working, and then randomly start working again.

We are having this same problem on my partner's machine. (He did not have Session Manager installed.) Quit a session the proper way, not via a crash, and when he re-started, his session was not saved. "Restore Previous Session" was available but did not do anything when selected. There were no numbered versions of sessionstore.js in his profile. His Privacy preferences were set to "Remember History," but in General the startup setting was "show a blank page," which he says he does not remember ever changing since the problem started.

When I checked his about.config, browser.sessionstore.resume_session_once was set to false, so I changed it to true manually. (I just checked my own settings and it showed the same, but I use Session Manager, which I've now had him install.)

So basically, I've looked at all the troubleshooting stuff above, and it looks like his preferences were set correctly, with one discrepancy in about:config, but Restore Session was useless and there were no other sessions in his profile. He hasn't encountered this problem before and hasn't made any changes to settings (he's not a big configurer of his machine or software, which is why I'm the one writing this up and troubleshooting for him.)

Can you tell me how to reset "browser.sessionstore.resume_session_once" to 'true' please? This just happened to me the other day, too.

Did you reset all the bolded things to normal? Please help.

Go to about:config, and search for sessionstore. If browser.sessionstore.resume_session_once is set to "false," double-click it to change it to "true." I'm not sure if this actually solves the problem, but it seems odd that it would be set to "false" with the settings choices we had in place.

Okay, I just did. Should I also reset a the bolded boolean-types to normal? I just did, and I'm not sure if I messed up on something.

And how does that get me my old browsing session back?

No idea about your question. And it won't get your session back - as far as I can tell, if there's not a sessionstore-##.js file in your profile, the session you lost is gone. You can re-create it via your history but that's stored by date, so if you've had tabs open for days or weeks you're SOL.

Install Session Manager for the future, that's all I can tell you.

I opened my session sessionstore.bak file into WordPad. Is there a way to get it back through this?

This is what makes Firefox a crappy browser. It'll completely screw up in some way (like deleting your session on restart), and then the only way to get help is in a lame forum like this, where half the responses are "I'm having the same problem," 25% of the other responses are ideas that might or might not work, and the other 25% are solutions that you either need an IT degree or a programmer friend with you to figure out. Thanks guys!