If you’re tired of losing your place when you close or restart Firefox, there’s a simple remedy: Turn on “Restore previous session” in Options, and you’ll get all your previously open tabs back the next time you restart. Here’s how to set it up.
First, open Firefox. In the upper-right corner of any window, click the hamburger button (three horizontal lines). In the menu that appears, select “Options.” (On a Mac, click “Preferences.”)
In the Options tab, select “General” from the sidebar, then locate the “Startup” section. Place a checkmark beside “Restore previous session” to turn the feature on.
After that, close the Options tab. The next time you restart Firefox, your tabs will be reloaded exactly as you left them before.
Note that this setting will not work if you have configured Firefox to always start in Private Browsing mode. That setting forces Firefox to always forget your browsing sessions every time you close it.