Do you mean that instead of opening your home page, your last session comes up when you start Firefox?

You may have corrupt sessionstore file(s). Delete all sessionstore* files and the sessionstore-backups folder.

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the above file. Then rename or delete it. Restart Firefox.

Don't delete the files if you need to rescue any data from them, just move them out of the profile folder to some location where Firefox doesn't look for them. You can try to read out their contents using this tool: https://www.jeffersonscher.com/res/scrounger.html

You can set this pref to 0 on the about:config page to get the about:sessionrestore page immediately with the first start after a crash has occurred or the Task Manager was used to close Firefox.

• browser.sessionstore.max_resumed_crashes = 0

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

See also:

• https://wiki.mozilla.org/Session_Restore#Preferences