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After closing firefox I am unable to log on again until I close the reuuning firefox

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The error message is: Firefox is already running but is not responding. To open a new window you must first close the existing Firefox process, or restart your system.

I always have to restart.

The error message is: Firefox is already running but is not responding. To open a new window you must first close the existing Firefox process, or restart your system. I always have to restart.

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Firefox is already running but is not responding

Plug-in and tasks started by Firefox may continue after attempting to close Firefox The "X" in the upper right-hand corner closes the Window (same as Ctrl+Shift+W) but even if it is the last Firefox window, it does not necessarily close Firefox .

The only proper way to exit Firefox is to use Exit through the File menu, not the "X" in the upper right corner of last Firefox window. In the Beta that would be Alt+F then X

Use the Windows Task Manger to remove all running firefox.exe in the "Processes" tab of the Windows Task Manager, then restart Firefox.

very unlikely occurrence: If Firefox will still not start, remove the parent.lock file from the profile which is created each time Firefox is started to prevent other Firefox tasks from running, see
http://kb.mozillazine.org/Profile_in_use#Remove_the_profile_lock_file

Avoiding Problems with close/restart

Use to close and restart Firefox after enabling or disabling an extension, switching to a new theme, or modifying configuration files, then you don't have to worry about delay or have to look in the Task Manager to see if Firefox is closed yet.

Keyboard shortcut "Ctrl+Alt+R" or a file menu option via ...