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FFis already running but not responding error.. Can't delete parent.lock "in use" What now?

  • 11 replies
  • 1 has this problem
  • 20 views
  • Last reply by cor-el

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I keep getting FF nor responding error. When I close it I get "your FF profile can not be loaded".

I read about deleting the parent.lock. When I try to delete it I am told "can not delete the file as it is in use".

So what do I do now to get FF going

I keep getting FF nor responding error. When I close it I get "your FF profile can not be loaded". I read about deleting the parent.lock. When I try to delete it I am told "can not delete the file as it is in use". So what do I do now to get FF going

Chosen solution

Can you delete the file immediately after booting the computer?

Does it help if you start Windows Explorer as Administrator?


You can create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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All Replies (11)

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You could try to use the Windows Task Manager to terminate Firefox.

You can launch that by pressing Ctrl+Shift+Esc, or it may be available from the Ctrl+Alt+Del list of options.

On Windows 8, you might not have an Applications tab in the Task Manager. In that case, check the Processes tab. Do any Firefox Windows show up here? If so, try to End Task on those windows.

Then check the Details tab for firefox.exe and if that is still running and refuses to shut down, try right-clicking it and choosing End Process (or whatever they call it in Windows 8 if different).

Will firefox.exe shut down?

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Thanks for responding.

I have used task manager as suggested but firefox does not appear in the processes/apps list.

Firefox is not running on my screen

When I try to launch it I get 2 error messages in sequence.

1 "FF is already running" (even though it is not in the task manager and not on my screen) So I click on either close firefox or cancel the two option on that popup message 

Then I get 2 "The profile can be loaded" error

So I searched the web. It told me to do the task manager idea you suggested but there is noFF there to delete. It then said to delete the parent.lock file.

I found this in the profile but when I try to delete it I get the error massage that "it can not be deleted because it is in use".
What do I do now?
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I just turned off my PC then did not turn on FF. I went to the profile and tried to delete the parent.lock file. It would not delete. I got the message "the action can not be completed because the file is open in Firefox"

I checked Task Manager apps and there is no evidence of FF.

Help!!
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I have scanned the disk for errors and got no errors.

The cause of this problem is probably that I tried to restart FF without letting it shut down completely.

Is the next step to create another profile using windows? or How do I delete the parent lock file when it keeps telling me that FF is using it and there is FF in the task manager?

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Chosen Solution

Can you delete the file immediately after booting the computer?

Does it help if you start Windows Explorer as Administrator?


You can create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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Thanks for the help. Yes I Can't delete parent.lock right after booting (I did not open FF) - it says that the file is in use by FF even though Task Mgr says there is no FF in Apps.

You said   -  Does it help if you start Windows Explorer as Administrator?

I am not sure what this idea means. I have tried to start FF as administrator and got the same 2 errors - not responding and profiles errors. No FF in Task Mgr. I am not sure about you talking about "Windows Explorer". I am using windows 8.1 and using the run command to access the parent.lock and profile. I did try to change properties of the parent lock file in Files Explorer (same thing?) but have no specific instructions for this so just played around. Got the same error "access denied as ff was using the file". Any instructions?

Is creating a new profile the only way? It seems complex. What could go wrong? There is no FF here so I have to use Windows to do this?

Modified by lenny@lweb.net

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To start Windows Explorer as Administrator, you could do any of these:

  • right-click a desktop shortcut for the program > Run as administrator
  • right-click a pinned Taskbar shortcut for the program, then right-click Windows Explorer > Run as administrator
  • open C:\Windows then scroll down to explorer.exe > right-click > Run as administrator

In this mode, the program may have additional features/options/powers not normally available to other users.

Edit: On Windows 8.1, if you go from the tiled Start screen to the program list screen, Windows Explorer might also be listed in the Accessories section.

Modified by jscher2000 - Support Volunteer

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Sorry I do not have windows explorer. I searched the C: drive and found 21 entries for explorer. 4 were explorer.exe.mui. No windows explorer exe. Some seemed related to internet explorer. I checked programs and have no windows explorer

From the tiled start screen if I use the search function I have no windows explorer only File explorer and Internet explorer. In My XP machine I have windows explorer though but it is a data logger not connected to the internet.

When I use File Explorer ( I think this is what you mean) I can get a properties function and have used it with the parent.lock file no change. I have used with FF to open as administrator no change same errors. I am not sure about what the functions of this properties function mean. What could I do to unlock the parent lock file?

What system are you using?

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Creating a new profile was relatively easy. Used directions as suggested above to create a new profile. I then used the run command with %appdata%\Mozilla\Firefox\Profiles in the box to get to the profile area and copy all the files from the old default profile to the "new" profile. Everything except the the parent.lock file. It was the problem.

I then opened FF using the the profile window using the "new" profile

I really missed FF so am glad it works. Big learning curve about profiles parent.lock and run command.

Thanks Cor el
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Glad you found a solution. I'm still using Windows 7, so I don't know all the changes in Windows 8 and 8.1.

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In Windows 8 it is File Explorer (previously called Windows Explorer).