Hello greierson,

Assuming I understand your question correctly, you don't want your Firefox to keep your windows and tabs from last session. If that's the case, you can take a look at this Restore previous session - Configure when Firefox shows your most recent tabs and windows on how to disable that option in settings (which should be under "Configuring session restore" in that page.

Alternatively, you can also look in the sessionstore.js under C:\Users\[your username]\AppData\Roaming\Mozilla\Firefox\Profiles\ and rename it to something else like sessionstore.bak.

Note that by default, file extension is not being shown in Windows 7 so you need to enable your settings to show file extension. You can refer this page on how to do it. Once you enable it, you can rename it to something else.

Hope that helps.

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Windows hides some file extensions by default. Among them are .html and .ini and .js and .txt, so you may only see file name without file extension. You can see the real file type (file extension) in the properties of the file via the right-click context menu in Windows Explorer.

Sorry, none of these suggestions helped. How do I delete the .js file that is causing my firefox to re-open with the previous tabs?

sessionstore.js

Type about:support in the address bar and press enter.

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

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

Perfect, at least for now. Thank you!