If you check the History menu, is "Restore previous session" available?

If it is available, does it work? Please note that you may need to use the Recently closed windows and Recently closed tabs lists after restoring a session, depending on how it was closed.

If "Restore previous session" is grayed out, then unfortunately you are already seeing everything that was available to restore.

There are some privacy/cleaning utilities that may remove session history and other kinds of browser history from time to time, including at Windows startup. Can you think of any software of that kind which might be touching your browser settings folders?

Thanks jscher2000, the Restore Session is greyed out and no, I don't have any windows utilities or firefox add ons that would interfere with history settings

Can Firefox restore your session if you exit out of Firefox normally and start it up again, without shutting down Windows?

If that doesn't work either, could you open a window and watch whether your session history files are being updated? Here's what I mean:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, click the "Show Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

Double-click into the sessionstore-backups folder and look for recovery.js. Firefox should be updating this file when you open new tabs, change pages in a tab, etc. By default, Firefox waits no more than 15 seconds after a change to update the file.

Does that seem to be happening?

Note: By default, Windows does not show the .js file extension. If you see a file named recovery which has the type JScript, that most likely is user.js. Or you can switch Windows to showing file extensions using the steps in this Microsoft support article: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

Try to 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 check for problems with the sessionstore.js file in the Firefox profile folder that store session data.

• 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).

Thank you cor-el

Is there documentation to show ALT+FILE+EXIT has a different behavior to clicking the 'x'(close window) when shutting down firefox? I am familiar that when resizing a Windows Explorer window using ALT+FILE+EXIT will save the settings. I would say I use the 'x' to close firefox 95% of the time, but it has always previously saved my tabs.

The links are helpful My last crash report was 3/11/2015 5:03 PM

Thanks

The close X on the title bar first closes the current window. When no windows are left then Firefox will try to close the browser. If there is a problem with closing the window then Firefox may not arrive at the code that closes the browser. The closing code may work differently when you close via the File menu or the power button in the Firefox menu button.

One difference I have seen in past thread: users have reported that when closing windows instead of using Exit -- for example, right-clicking Firefox on the Windows Taskbar and using Close All Windows -- if there were more than 3 windows open, Firefox was unable to restore more than 3. Probably because, by default Firefox only keeps 3 previously closed windows in session history. When using Exit, all windows are treated as having been open rather than only the last one closed being treated as open. This might have been fixed by now, I haven't tested for obvious reasons.