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All of your personal settingsbookmarks and other information are kept in your Firefox profile. Firefox needs an unlocked profile to start upand if the profile is lockedit displays the messageFirefox is already runningbut is not respondingA copy of Firefox is already open. This article explains what to do if you see this message and how to prevent it from showing at startup.
Table of Contents
End Firefox processes
If Firefox did not shut down normally when you last used itFirefox might still be running in the backgroundeven though it is not visible. If you try to open it while it's runningan error message will appear with the option to click . If that doesn't solve the problemrestart your computer or try the following options. Restart your computer to see if the problem goes away or try the following options.
Ubuntu Linux
- Click and choose .
- In Administrationclick . Here you will find firefox-bin one or more times.
- Highlight the listing and click for each one.
Use the Windows Task Manager to close the existing Firefox process
- Right-click on an empty spot in the Windows task bar and select (or press Ctrl + Shift + Esc).
- When the Windows Task Manager opensselect the tab.
- Select the entry for firefox.exe (press F on the keyboard to find it) and click .
- Click in the Task Manager Warning dialog that appears.
- Repeat the above steps to end all additional firefox.exe processesthen exit the Windows Task Manager.
- Start Firefox normally.
Use the Windows Task Manager to close the existing Firefox process
- Right-click an empty spot in the Windows task bar and select (or press Ctrl + Shift + Esc). When the Windows Task Manager opensit defaults to the tab.
- Right-click the collapsible entry for Firefox (press F on the keyboard to find it) and select from the context menu. This will close all Firefox windows with no additional prompting.
- Exit the Task Manager and start Firefox normally.
Remove the profile lock file
Firefox may have shut down abnormallyleaving the lock file in place. To fix thisopen the profile folder (see Finding your profile without opening Firefox) and delete the parent.lock file lock and .parentlock files.parentlock file.
Remove the -no-remote startup option
If you start Firefox with the -no-remote command line optiontry removing this option.
Initialize the connection to a file share
If you store the profile on a file sharetry accessing the file share beforehand using Windows ExplorerFile Explorer.
Check access rights
Firefox must also have the right to create files in the profile folder. The error can occur if you try to use a profile from a file system mounted with read-only permission (for examplea remote Windows share which doesn't have Allow network users to change my files checked).
To ensure your profile folder has the proper permissions:
- Find your Firefox profile folder.
- Right-click your profile folder and select .
- In the tabmake sure Read-only is not checkeduncheck Read-only (Only applies to files in folder) (if it is not already).
- Find your Firefox profile folder – see Finding your profile without opening Firefox.
- If you only have one profileits folder would have “default” in the name.
- Hold down the Ctrl key while you click your profile folderand select .
- Make sure Ownership & Permissions is set to Read & Write.
- Find your Firefox profile folder – see Finding your profile without opening Firefox
- If you only have one profileits folder would have “default” in the name.
- Right-click your profile folder and select .
- Click the tab.
- Make sure Folder access is set to Create and delete files.
Restore data from a locked profile
If you are unable to unlock the profile using the above methodsuse the Profile Manager to create a new profile and migrate your data from the locked profile to the new profile. For information on how to do thissee Restore bookmarkspasswords and data from an old Firefox profile.
Based on information from Profile in use (mozillaZine KB)
