Does your Firefox record tab and window history normally during regular use? For example, if you open a new window using Ctrl+n, then close the window, can you re-open it using Ctrl+Shift+n or the menu item here:

• "3-bar" menu button > Library > History > Recently closed windows
• Library toolbar button > History > Recently closed windows
• (menu bar) History > Recently closed windows

Please also make sure Firefox doesn't delete browsing history at shutdown. You can check that here:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security

On the right side, scroll down to the History section. Usually it says:

Firefox will: Remember history

If it says

Firefox will: Use custom settings for history

make sure this box is not checked:

[_] Clear history when Firefox closes

If it says

Firefox will: Never remember history

that setting is not compatible with restoring your session.

Was everything okay there?

Ctrl+Shift+n works; also, Ctrl+Shift+T after closing a tab. History section says: Remember history

Just discovered that when I open Firefox again, and get one tab on my home page, if I click on recently closed WINDOWS, I see a icon that will open my last session as a new window.

Nevermind. Problem was that a second Firefox window was opened, probably as I was just beginning to use it--I just installed it--and I didn't notice. So I was using, and then closing that second window, and that's why when I opened Firefox again, I got the blank window. When I discovered the old, original window--I have 20 windows open; that's normal--and closed it, when I opened Firefox again, there were all the tabs. I think I'll go have a beer.

Glad you sorted it out. I always close Firefox using the menu to avoid having the wrong windows in a "closed" status:

• "3-bar" menu button > Exit
• (menu bar) File > Exit
• (keyboard) Alt+F then x

Good suggestion. Thanks for your help.