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 at any time.
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 4 saves the previous session automatically, so there is no longer need for the dialog asking if you want to save the current session." What? The problem is that Firefox 4 DOES NOT save the previous session, and it gives you no option to save the previous session. Telling it to open tabs and windows on starting does not work, and the "restore previous session" under history is blanked out so it cannot be clicked on. The entire reason to use Firefox was its superior tabs and windows and the ability to control them and save them and now this has been totally eliminated from FF4! Why?

I agree with mrpoizun. I liked everything about Firefox before 4. This automatic saving of sessions has one big flaw! When opening FF, it shows a blank screen (simply because my innitial preference is to start on blank). If I should change my mind or accidentaly close this, the blank is saved, or rather the previous session is deleted. The Restore option is disabled. I request that "Save & Quit" be restored!

Hm. Wonder if there is anything in my browsing habbits that requires FF4? If not, then I'll just try to find an earlier installation file.

Make sure that you not run Firefox in (permanent) Private Browsing - Use Firefox without saving history mode.

• You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"
• To see all History and Cookie settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history
• Uncheck: [ ] "Permanent Private Browsing mode"

Actually, better yet. How about allowing us to save our window/tab sessions as files? A new option apon closing: "Save as & Quit" and add an arrow to the "Restore Previous Sessions". When I'm at home, or properly connected, I always like to have my set of tabs open automatically. However, there are times when I go to places where the connection is limited and that is when it might not be a good idea to start downloading so many sites at once (where as load blank page comes in handy). Before I used to save my tabs to bookmarks, but it would actually be better if I got the choice like just before shutting down and heading off to the new place.

• Session Manager:https://addons.mozilla.org/firefox/addon/session-manager/

I tried the session manager addon. It doesn't work; firefox still does not save any tabs or windows. Unbelievable. How could they screw up this release so completely?

OK. If you download the session manager addon, and go to Tools- Options- General, at the top where it says, "When Firefox Starts" choose "show selected session manager session". Even after using CCleaner, I am getting my tabs back. No guarantees, but this does seem to be working for getting tabs back upon opening the browser. However, there is no option to save or not save tabs and windows on closing. Good luck to everyone else trying to unscrew up this pathetic new release.

"Even after using CCleaner..."

Interesting bit of information that you neglected to provide before you "went off" on a rant about how pathetic Firefox 4 is. Clear your browsing history and then complain when Firefox doesn't show your previous session. Apparently common sense isn't all that common.

Yes, the Session Manager will save sessions when using CCleaner, that extension stores your session information in a different file than Firefox does, where CCleaner doesn't look for it.

As I said and you quoted, it worked even when using CCleaner. It also worked when not using CCleaner. And I was not using CCleaner when I was trying all the other ways to get FF4 to save tabs and windows. The point is, I shouldn't have had to screw around at all to retain the save tabs function. Who is it that lacks the common sense necessary to understand plain English?

I go to "file"..."exit" and lose my tabs when I reopen! Firefox will not remember the last session and always opens with a new home page. How do I fix??? Thanks

ps....I have already ticked the right boxes as advised above. I don't have CCleaner on the netbook.

Can you still access that session via "Firefox > History > Restore Previous Session" ?

Make sure that you not run Firefox in (permanent) Private Browsing - Use Firefox without saving history mode.

• You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"
• To see all History and Cookie settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history
• Uncheck: [ ] "Permanent Private Browsing mode"

Menu Bar: Click "Tools>>Options>>General," then in "Startup", "When Firefox starts," select "Show my windows and tabs from last time". Works for me. Also, I love the add-on, "Session Manager". (:;)!

I use Tab Mix Plus 0.3.8.6 as session manager add-on and still this was not working untill I've unchecked the checkbox "Use Firefox's built-in Session Restore feature" in the options window of that add-on.

Same problem with FF 6.0 on Win 7. Didn't have this problem with XP. So maybe this is something 'new' (and better?!) with FF6.0?