To try to restore the missing window, right-click the little thumbnail image and choose Maximize.

Does that bring the window back? If so, the window probably got "off screen" somehow.

If that doesn't work, hmm, a ghost. Was it a full-screenedFlash player? Perhaps it crashed in some terrible way that Firefox is confused about...

Could you also try right-clicking the Firefox button and choosing "Open New Window" or clicking Mozilla Firefox on the lower part of the list to launch a new Firefox window.

Then check whether you can re-open the game from the closed windows list. This list is available in two places:

• "3-bar" menu button > History - under the heading Restore closed windows
• classic menu bar: History > Recently closed windows

Anything?

Thanks, jscher, but it wasn't a minimize/maximize issue. The fullscreen is just not available. Anyone else?

I'll try those alternatives, too. Thanks

LeBlancD said

Thanks, jscher, but it wasn't a minimize/maximize issue. The fullscreen is just not available.

If a resizeable window is positioned off screen, maximize usually works to make it visible. Please try it for diagnostic purposes.

Did you try to close and restart Firefox to see if that bring back the window?

You can check if you can start Firefox in Safe Mode by holding down the Shift/Options key.

You can try to start Firefox with the about:blank page by creating a copy of the current Firefox desktop shortcut and add a space and -url "about:blank" to the target field.

you might have set-up a dual screen system where all the apps now open on an invisible second screen. if your monitor is connected with two vga/dvi/hdmi(or whatever)-cables the same time, please remove one of them as this might confuse your computer.

after you've clicked on an application icon on the windows taskbar you might also want to try to press the windows-key+arrow-left shortcut multiple times to move an application to another screen...

phillip - this didn't work. I've had the same setup for three years without multiple cables. I don't understand what your second suggestion is.

please try to launch firefox into safemode by pressing the shift key after you click on the firefox icon as already suggested by cor-el. in case this works you can either refresh firefox or continue in safemode & go to the firefox menu ≡ > help ? > troubleshooting information, click on profile folder/show folder and close all firefox windows afterwards. a windows explorer window should open up - in there delete the file named xulstore.json - afterwards try to restart the browser normally.

I've tried all of the suggestions, the window doesn't come back. I thought I would uninstall and reinstall Firefox, but will that lose my bookmarks? Will that even work?

If you use the option to remove personal data while uninstalling, then that will delete your bookmarks. Otherwise, your personal settings folder should not be affected.

To check whether this is an issue in your current settings, you could try this 3-minute experiment:

Create a new Firefox profile

A new profile will have your system-installed plugins (e.g., Flash) and extensions (e.g., security suite toolbars), but no themes, other extensions, or other customizations. It also should come with completely fresh settings databases and a fresh cache folder.

This does not replace your existing setup; the new folder exists in parallel with your current settings.

Exit Firefox and start up in the Profile Manager using Start > search box (or Run):

firefox.exe -P

Don't delete anything here.

Any time you want to switch profiles, exit Firefox and return to this dialog.

Click the Create Profile button, assign a name like March31, and ignore the option to change the folder location. Then start Firefox in the new profile you created.

Is the window visible?

When returning to the Profile Manager to switch back to your normal profile, you might be tempted to use the Delete Profile button. But... it's a bit too easy to accidentally delete your "real" profile, so I recommend resisting the temptation. If you do want to clean up later, I suggest making a backup of all your profiles first in case something were to go wrong.

Or if you stick with the new profile, you can restore a backup of your bookmarks into the new profile as follows:

Open the Library dialog (Ctrl+Shift+b or "Show All Bookmarks") to access the Restore feature. The trick is knowing where to find your bookmark backups in your regular profile. After clicking Choose File... you can paste this into the file name space and press Enter to drill down to your profile folders:

%APPDATA%\Mozilla\Firefox\Profiles

The semi-randomly-named folder that has your last backup is usually the one ending with "default". Click into that one, then into the bookmarkbackups folder. Here you can pick the most recently updated file to restore.

Important: a Restore wipes any bookmarks currently in your currently active (brand new) Firefox profile and replaces it with the contents of the restored backup.