The .Tabs. filters were already set to TRUE but the ones in step 6 were set to FALSE and changing them to TRUE solved the problem! Thank you! I was just about to pull the plug on v4.0

I found the solution and it is really easy. Click on Tools, Options and Under the General Tab, where it shows your home page... click the down arrow and select Show my windows and tabs from last time. Then click OK.

While I would prefer to see something like a check box within the Tools/Options choices, this solution worked for me (of the 4 settings, 2 were already "true"), and it took all of 60 - 90 seconds to complete. It will take something far worse than this to drive me to a fruit browser! PS - thanks for the clear instructions in the post.

Why was this setting changed? Was there a problem with it? If not, why remove a functioning setting that people are used to?

Changing about:config worked, but it seems an arbitrary and capricious decision on the part of the developers to remove this as a default setting.

The replacement setting is not the same as this previous one--I don't always want to restore a session, and I would like to choose when to do so.

Arrogance.

People, when you post a reply, try reading the question first. I had this same issue and finally realized that this functionality is provided by an add-on called Tab Mix Plus. (It may never have been part of Firefox's built in functions, I don't have time to investigate)

Here's how to actually solve your issue, using the path of least resistance. (i.e. no screwing around with about:config options)

Install Tab Mix Plus Add-On from here: https://addons.mozilla.org/en-US/fire.../tab-mix-plus/

Set the options as indicated in the Tab Mix Plus options menu illustrated in Image #1

When you close your browser, you will now get image #2

So elegant, so simple, it's startling that this is not a built in feature.

Lastly, go thank Add On developer for making your life simpler, and if you're rich don't be a parasite, give him money.

vancedecker:

There were options in Firefox 3.6 to save open tabs when closing Firefox. There is a change in the way that Firefox 4 performs that function and many users are accustomed to seeing the "Save tabs" window when exiting Firefox.

Tab Mix Plus is a good add-on but is not ideal for everyone. TMP can be over-whelming for some users, therefore I did not mention it. In addition, many users do not want to add another extension to re-gain functions that they are accustomed to seeing in Firefox. I use TMP but, as I said, it is not meant for the casual user who does not need the power and extensive options offered.

Why even make it so we have to screw around with all this stuff to begin with? It worked just fine before. My problem is that the solutions given in this thread worked and out of nowhere, it doesn't work anymore. My session is not saved in spite of the fact that everything is the same (the preferences thing says show previous session tabs, the about stuff is all on true). So it'll work, but only for a couple weeks. And the tabs add-on a) isn't worth it and b) shouldn't be needed when the save session option was a standard feature. FF4 is too Internet Explorer for my tastes. Looks the same, acts the same. Why should I even use FF?

Why even remove this very useful feature in the first place? Why do we people like to complicate things for ourselves and others? I can never understand!

1. Saving tabs was not removed from Firefox 4, but it works a bit differently.
2. Some users want the warning dialog when closing Firefox to show so that they can make a decision about whether to open the current tabs when restarting Firefox the next time. This is what the original poster was requesting.
3. By default, Firefox 4 will not ask to save tabs, but instead it will always save your tabs on exit unless you are in Private Browsing mode. You can restore them next time by:
   • clicking Firefox button > History >"Restore Previous Session", or
   • type about:home in the URL bar and press the Enter key, then press the "Restore Previous Session" button
4. Note: This was a decision by the developers. On this forum, we are all uncompensated volunteers here to help other users. The developes/employees of Mozilla/Firefox rarely, if ever visit here.

Some things to check:

1. Browsing history must be saved
   • Firefox button: Firefox button > Options > Options > Privacy > [X] Remember my browsing history
   • Menu Bar: Tools > Options > Privacy > [X] Remember my browsing history
2. Also make sure you do not clear "Browsing History" when using Clear Recent History or when closing Firefox
   • Using Clear Recent History
     • Firefox button: Firefox button > History >Clear Recent History
     • Menu Bar: Tools > Clear Recent History
   • When closing Firefox
     • Firefox button: Firefox button > Options > Options > Privacy (checked) > Settings
     • Menu Bar: Tools > Options > Privacy (checked) > Settings
     • See: https://support.mozilla.com/en-US/kb/Clear%20Recent%20History
3. Make sure you are not in Private Browsing mode or in permanent Private Browsing mode:
   • See: https://support.mozilla.com/en-US/kb/Private%20Browsing
4. If you have theTab Mix Plusextension, then disable the built-in session restore.

To display the "Save Tabs and Exit" message when closing multiple tabs, you can do the following:

1. Type about:config in the URL/Location/Address bar and press the Enter key
2. Accept the warning message (promise to be careful)
3. The preferences page/list will open
4. Filter = browser.tabs.warnOnClose
5. If its value is set to false, double-click on it (in the lower panel) to toggle its value to true
6. Repeat steps 4 and 5 for these following 3 preferences also:
   • browser.warnOnQuit
   • browser.warnOnRestart
   • browser.showQuitWarning
     • Note: last pref is new in Firefox 4b12, may need to add (boolean)
     • Info/Instruction for using about:config: http://kb.mozillazine.org/About:config
7. See:
   • https://support.mozilla.com/en-US/questions/785169
   • http://forums.mozillazine.org/viewtopic.php?f=23&t=2105039&p=10434467&sid=fd2a35945bb2c633687f7b50d8c53989
   • http://blog.zpao.com/post/3174360617/about-that-quit-dialog