Your user.js file would be in your profile folder. You can check for it this way:

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.

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup, then scroll down and rename user.js to something like userjs.old.

By default, Windows hides the .js file extension, so you may see a file named user of type JScript, which is the user.js file. I suggest forcing Windows to show ALL file extension to make it easier to manage file renaming. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions#show-hide-file-name-extensions=windows-7

Start Firefox back up again. Do you get your home page as expected?

Three other notes:

(1) The user.js file should not be recreated immediately after you use the Refresh (Reset) feature. Some other program on your computer would have created that. But what program? Hmm... have you noticed any other modified settings that might point toward a particular culprit?

(2) It is normal for Firefox to save your tabs so you can restore your previous session on demand, even if you prefer to start up with your home page. But you should be in control of this.

(3) Firefox will try to restore your previous session after a crash. Maybe Firefox crashing during shutdown? Using the menu to exit (as described in the earlier reply) can help with this problem; there are many more shutdown crashes using the "red X" button than the menu.

You also can change a setting so that instead of automatically restoring the session after a crash, Firefox presents a screen with a list of your windows and tabs and gives you the option to restore them or just start a new session. Changing this setting would be helpful in diagnosing whether your session is being restored due to crash recovery or some kind of settings override. If you want to try it, here's how:

(A) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(B) In the search box above the list, type or paste sess and pause while the list is filtered

(C) Double-click the browser.sessionstore.max_resumed_crashes preference and change the value from 1 to 0 and OK that.

Note: Please don't change any other sessionstore preferences without researching them first.

Can you post the content of the user.js file?

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.

Thanks jscher2000 someone finally was able to explain where and what I was looking for in detail. It looks like that might have fixed my problem.