Hi Mill14

Use "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit) to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar.

You can try to rename (or delete) the sessionstore.js file and possible sessionstore-##.js files with a number and sessionstore.bak in the Firefox profile folder.

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Multiple_profile_files_created

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible).

Hi Edward27821

In case you are using "Clear history when Firefox closes":

• do not clear the Browsing History

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings
• https://support.mozilla.org/kb/Clear+Recent+History

Note that clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, passwords, and other website specific data.

Which pages do you want to open on startup?

You can check the home page setting:

• Tools > Options > General > Startup: Home page

Firefox supports multiple home pages separated by '|' (pipe) symbols.

• https://support.mozilla.org/kb/How+to+set+the+home+page

You can check the target line in the Firefox desktop shortcut (right-click: Properties) to make sure that nothing is appended after the path to the Firefox program.

If you use "When Firefox Starts":
"Show my windows and tabs from last time" and this isn't working then that would indicate that there is a problem with Session Restore.

You can reset browser.sessionstore.* prefs on the about:config page that are user set (bold) via the right-click context menu to the default value to make sure that Session Restore is enabled and working properly.

• http://kb.mozillazine.org/Session_Restore
• https://support.mozilla.org/kb/restore-previous-session

You can check for problems with the sessionstore.js and sessionstore.bak files in the Firefox profile folder that store session data.

Rename (or delete) the sessionstore.js file and possible sessionstore-##.js files with a number and sessionstore.bak in the Firefox profile folder.

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

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible).

You're welcome Edward27821.

I've posted a for Mill1 above, so we need to wait for feedback to see if that had helped.

Hi Mill1,

Could you clarify what is in the second window that currently opens when you start Firefox?

Glad you're all set Edward!

The second window that opened when my daughter did something (dragged a tab or something?) was just a regular, new "default" Firefox window containing one of the tabs that I had had opened on my first Firefox window (which was still there, but maybe it was closed before the second window, which caused the issue ????). It looked like a Firefox window that hadn't been customized with pinned tabs or homepage.

I renamed the sessionstore files, but it didn't make a difference. I think it is because they had been updated with the new session I used yesterday which did not contain my info. That's fine, I can recreate all of my pinned tabs and homepage again. Once I do that, can I make a copy and rename the sessionstore.js and sessionstore.bak with a number (or my name) so that I have a spare? Then in the future if this type of thing happens again I can just go in and delete the current sessionstore files (that are messed up), copy/paste my "spare" files and rename them so they don't have the number (or my name) so that those files are used next time I open Firefox?

Yes, you can tear off a tab to a new window by dragging the tab slightly down in the browsing window.

If this happens then you can drag this tab back to the tab bar in the original window to undo this tearing off.

Pinned tabs are restricted to one window (each window can have its own set), so it is no surprise that you didn't have the pinned tabs in that second window. If you closed the original window then you can try to see if you can restore this window via "History > Recently Closed Tabs/Windows". Otherwise this window is lost and you will have to recreate the lost pinned tabs in the current window.

Thank you. It sounds like that's what happened this last time. I don't know what's caused it in the past, but I'm just tired of having to recreate the pinned tabs over and over. Can I do the sessionstore file renaming thing as a backup if the "History > Recently Closed Tabs/Windows" thing doesn't work?