Firefox 4.0 has a new feature that automatically saves your tabs when you close Firefox. You can Restore Previous Session from the about:home default homepage hyperlink under the Search container or access that item from the History menu.

You can set this hidden pref to what you want, to give the warning when closing multiple Tabs, if you feel more comfortable with seeing that message.

1. Type about:config into the location bar and press enter
2. If you see the warning about accessing those prefs, you can confirm that you want to access that page.
3. Type browser.tabs.warnOnClose in the Filter line at the top, and that pref will appear. If its value is set to false, double-click on it to change its value to true.
4. Then restart Firefox.

Really? Then this new feature doesnt work properly, because everytime I close Firefox and start new, the tabs are gone. Is there a way to fix this? Thanks

It is missing for me also. I tried the solution given but it was already set to 'true'. Just doesn't seem to be working.

Would really like a solution as I rely on this and don't really want to have to restore previous session each time. I want it to happen automatically.

You can use "Firefox > History > Restore Previous Session" to get the previous session.
There is also a "Restore Previous Session" button on the default about:home Home page.

Another possibility is to use:

• Firefox (Tools) > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"

Make sure that you do not use Delete browsing, search and download history on Firefox to clear the 'Browsing History' when you close Firefox.

Thank you.

I have this problem, too. I appreciate that there are 'solutions' to fix it, but I wish they would just make it the default option as in the previous versions of Firefox. I am seriously displeased with this newest upgrade, which is disappointing because Firefox has always been my favorite and vastly preferred browser.

I've had to revert to IE which I loathe, but 4.0 is much too buggy for me. :/

You can set the warn prefs on the about:config page to true via the right-click context menu or toggle the value with a double left-click.

• browser.showQuitWarning, see http://blog.zpao.com/post/3174360617/about-that-quit-dialog
• browser.tabs.warnOnClose, see http://kb.mozillazine.org/About%3Aconfig_entries
• browser.warnOnQuit , see http://kb.mozillazine.org/browser.warnOnQuit
• browser.warnOnRestart , see http://kb.mozillazine.org/browser.warnOnRestart

I agree. I have no clue why they would have changed this great feature. I am not going to bother waiting for a fix. I'm dumping the new Firefox 4 and reinstalling the old one--if I can! I'm no techie and I hate having to do things like this.

Why would they even have thought that it was a good idea to change this feature. I discuss it with all my friends and they all love it.

Firefox 4 saves the previous session automatically, so there is no longer need for the dialog asking if you want to save the current session.
You can use "Firefox > History > Restore Previous Session" to get the previous session.
There is also a "Restore Previous Session" button on the default about:home Home page.

Another possibility is to use:

• Firefox (Tools) > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"

Firefox (Tools) > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time" and not "my homepage"

#This will fix the problem for most I think:

Firefox 4.0 has a new feature that automatically saves your tabs when you close Firefox.

Its seems that for many people, this feature was not enabled automatically, instead it is set on a different setting of 'show my homepage' or 'show a blank page'. But it is very easy to change, I just did it myself! Here is how to do it:

At the top left of the screen is an orange 'Firefox' box, click on it. On the right of the dropdown menu you will see 'Options'. Click on it. Then you will see another 'Options', click on it. This will bring up the Options menu.

The part we are interested in for this fix is where it says, 'When FireFox starts:'. There is a dropdown selection next to that sentance, click on the little down-arrow, and choose ' Show my windows and tabs from last time'. Then click on 'OK' at the bottom of the Options menu, this will close the menu.

You should be sorted now, I was. I hope it works for you too. To test it out, have a few tabs open, and close firefox. Then try open it. Those same tabs should re-appear. Holding thumbs & fingers crossed :)

OMFG thank you so much everytime i update the firefox i always have the issue with save an quit with the last one i went though soo much trouble i was looking for HOURS an your comment fixed it in like one minute THANK YOU SOOOO MUCH!!!!!!!

Something else is going on here besides all the "options" that everyone else has already suggested. I already had ' Show my windows and tabs from last time' checked.

I've lost the history from the last 8 hours ... there's absolutely nothing between 6AM and 2PM. I just installed some Windows upgrades. When I clicked to restart my computer, FireFox was not responding AGAIN, so I closed it.

When I finally got FireFox running again, the 4 open tabs that I left open were not there. Nothing in history between 6AM and 2PM. And every single time I log out of Gmail, I lose all the dropdown account selections (5 accounts between 2 people).

Is the history only saved when FireFox is closed 'correctly'??

I don't have an orange firefox "box" at the upper left, I have a round orange and blue firefox symbol. And the menu that drops down does not include "options".

If you want to download previous version go to

http://www.mozilla.com/en-US/firefox/all-older.html

the Option ' Show my windows and tabs from last time'

Does this open your preset Homepage regardless of whether it was open in the last session and any other tabs open from the last session?

-- What I did was this:

firefox->tools->options-> general tab-> when firefox starts-show my windows and tabs from last time-This fixed my problem completely! Thanks so much!! 

As soon as I did this, my problem was fixed. it was like BAM! Why didn't I do this before? I was doing the happy dance. Thanks again!

Toad-hall-- No it does not- It opens up the tabs you had open the last time you had firefox open. I use this- when i start up firefox, it opens everything i had open. i use facebook, then twitter and other tabs as well. they all open back up when firefox is started.

Make sure that you do not use Delete browsing, search and download history on Firefox to clear the 'Browsing History' when you close Firefox.

• https://support.mozilla.com/kb/Clear+Recent+History
• https://support.mozilla.com/kb/Firefox+does+not+ask+to+save+tabs+and+windows+on+exit

See also:

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

You can set the warn prefs on the about:config page to true via the right-click context menu or toggle the value with a double left-click.

• browser.showQuitWarning, see http://blog.zpao.com/post/3174360617/about-that-quit-dialog
• browser.tabs.warnOnClose, see http://kb.mozillazine.org/About%3Aconfig_entries
• browser.warnOnQuit , see http://kb.mozillazine.org/browser.warnOnQuit
• browser.warnOnRestart , see http://kb.mozillazine.org/browser.warnOnRestart

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

• Use the Filter bar at to top of the about:config page to locate a preference more easily.
• Preferences that have been modified show as bold(user set).
• Preferences can be reset to the default or changed via the right-click context menu.