If you want to open Firefox and have all the windows and tabs from last time displayed : from the Firefox button-->Options-->General-->When Firefox starts-->Show my windows and times from last time,also you can quit Firefox by clicking Exit either in the File menu or in the Firefox button menu,instead of using the close button in the rightmost corner.

That would work and that is what I did on the Firefox 3.xx versions but in the Firefox 4 that is not an option on the General tab or anywhere else. I have been able to restore my previous tabs by going to History-->Restore Previous Session I just wondered if there was a way to do the same thing.

I'm sure he option we are talking about is still there,you can access it either from the Firefox orange button menu or from the Menu bar (ALT key to toggle it if it's not displayed) -->Tools-->Options.

Also,the default Mozilla Firefox Start Page should now display an hyperlink at the browser restart,pointing to the same session restore option you have used.

This answer may also be useful

Here's a screenshot to prove the option is availible:

Sorry, go lost in all the clicking I did to find it. Thanks!

Pat

Mark's solution works, but now, even with the "warn when closing multiple tabs" on, I don't get the warning any more and firefox just exits without a dialogue box.

Type "about:config" in the address bar and search for "showQuitWarning". browser.showQuitWarning will pop up. Right-click on it, and click "Toggle". It should now turn bold, and on the right-most column it'll say "True". And there you go! Now it'll ask you if you want to "Save and quit", rather than "Close all tabs".

I can't select save windows and tabs from last time as it is in gray

Looks like you were in Private Browsing - Use Firefox without saving history mode.

No it won't.. :-) I just tried that and it closes as it did before..

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"

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

Yes, it is logic. If it already saves all the tabs doesn't ask if we want to close them.. But, in case we hit the X button by mistake, at least we had a chance to cancel.. But it is a minor problem for me. The important is that I have my tabs everytime I launch Firefox. great prog by the way. Lovin' it  :p

i guess 'save' means something different than 'bookmark' to the majority of people? is it just me then or is anybody missing the 'bookmark all tabs...' menu option that used to be under 'bookmark this page' and 'subscribe to this page' in firefox 3.6 ? open my last session? yeah great. do i want to have the same session every time? no. do i want a better way to save all my tabs in one window in a nice little folder rather than saving all 24 of them one at a time? yes. plus who wants to quit firefox and then reload their 5 windows of 10 tabs each all at once? thats slow and bad enough when it crashes and you have to. why would they take away the bookmark all tabs menu item, the most useful thing created since the tabs themselves.?????????? it defies logic.

@jonathan5175172 The option to "Bookmark All Tabs" is availible. Just right click any tab and in the dropdown menu that appears select that option. See the screenshot below.

Instead of closing with the x at the top right, Go to Firefox menu and use Exit. Next time you open all your tabs will have been saved.