Firefox process is already running windows

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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 have tried

• 2 replies
• 55 have this problem
• 5820 views
• Last reply by cor-el

After deleted profile my Firefox will not start Message — 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 have tried – Restarting — Checking control panel for active firefox.exe –Uninstal l- Reinstall- and run CCleaner. All without any result

Can You help me? Are there any other processes that can be running? Is there any cleaning tool available?

Best Regards, Pelle

Chosen solution

Why did you delete your profile? Also how? Did you use the profile manager or did you delete from the windows file structure?

Firefox process is already running windows

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Suggested solutions do not work for «Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window.»

• 4 replies
• 13 have this problem
• 1783 views
• Last reply by rambosauce

I keep getting the error «Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window.»

I attempted all recommended steps I could find on support (task manager, profile permission settings, etc.) and none of which worked. I even uninstalled Firefox and used other browsers for over a month. Upon reinstallation and launch I keep getting the same error. At this point I’ve exhausted all the advice I could find on this forum and hope I do not have to abandon Mozilla.

Chosen solution

Thank you both for the reply, I understand things are busy.

I am on Windows 7 and had previously tried reinstalling the newest version of Firefox.

I went a little aggressive and deleted the entire Mozilla folder in the AppData directory. Now the newest version has installed and launched with no problem 🙂

Reinstalling plugins is trivial to go back to using my favorite browser. Cheers!

Firefox process is already running windows

Hello, I got this issue where I’m logged into more then on computer at a time. If I have Firefox running on one computer I’m prevented from running Firefox on anther computer. This because my user account has its home directory mounted across all the computers. It appears that the lock file is preventing from running Firefox on the 2nd computer. What I have been doing is deleting the lock file in my home directory. Then I’m able to start Firefox on the 2nd computer. Is there a better way of doing this? Is there away to disable the use of the lock file? Now I could just exit out of Firefox on the 1st computer but what if I’m running a web app on the 1st computer. What if you are using a shared admin account to such as root or using a RBAC profile. If user1 is using Firefox after become root or assuming a role, then no other user can use Firefox as root or using that role. That makes it very hard to use Firefox then. Anyway this is mostly a UNIX/Linux question.

Выбранное решение

Hello, I thought I should update this post with the answer.

In order to get around the lock file. You can delete it or use profiles. If your running Firefox from a UNIX, BSD or Linux based OS. To get to the profile popup window use the -p option.

Which will look like the image below.

To get the popup all the time uncheck the «Don’t ask at startup»

If you don’t have a GUI running then you can do this.

firefox -CreateProfile profilename

Firefox process is already running windows

I am running Windows 7 with 3 different user profiles, all of which run Firefox seamlessly, but one. I have tried the different options listed on the main forum for this; however, the issue persists. I have uninstalled and reinstalled the application, with no success. The only thing I did have problems understanding/completing was finding the profile for the one user>parent.lock file. I never found this file. I’m not sure, at this point, what else to do. I have run a virus scan and it’s all good. Any suggestions? What am I missing here?

Выбранное решение

Create a new profile as a test to check if your current profile is causing the problems.

See «Basic Troubleshooting: Make a new profile»:

There may be extensions and plugins installed by default in a new profile, so check that in «Tools > Add-ons > Extensions & Plugins» in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

Все ответы (5)

Выбранное решение

Create a new profile as a test to check if your current profile is causing the problems.

See «Basic Troubleshooting: Make a new profile»:

There may be extensions and plugins installed by default in a new profile, so check that in «Tools > Add-ons > Extensions & Plugins» in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

I ended up creating a new user profile and transferred his files to his new user account. Thank you so much for your help and your fast response!

I don’t have much difficulty with this problem. It’s more of an annoyance.

A frequent annoyance.

What I’ll do is log in to a page that requires a secure connection, and when I’m finished, to complete the security, I always close the browser. Then, of course, I start the browser up again.

The problem is, Firefox is still shutting down, and issues this error. Most of the time, I can wait 10 seconds, then start up fine.

So my question is, why the heck can’t the process that detects that Firefox is still running do the waiting for me? Instead of popping up a message, «Firefox is still running», pop up a message, «Firefox is cleaning up from the last shut-down, one moment please», then start up again.

I hate to mention it, but none of Firefox’s competitors have any problem with starting up too soon after a shut-down.

Firefox process is already running windows

I missed this part:

It seems to be an independent process closing which doesn’t affect Firefox at all, even while running but the location of this process is still the Firefox.exe in the install directory.

Does the command line show a particular profile being used or any other unusual parameters?

That’s the issue. I thought it was some malware, and it still could be I’m still trying to see, but when i went to the details of the process, it was firefox.exe and when i opened the file location of the process it was the .exe file in the folder in which firefox is installed. That is what confuses me, it looks legit.

And how do I see the parameters and what would be considered unusual?

Phoenix Shade [[#question-1291454|said]]

It seems to be an independent process closing which doesn’t affect Firefox at all, even while running but »’the location of this process is still the Firefox.exe in the install directory»’.

Does the command line show a particular profile being used or any other unusual parameters?

And how do I see the parameters and what would be considered unusual?

Add the Command Line column to your Details tab in the Windows Task Manager.

Normally, the main process Command Line looks like this:

«C:\Program Files\Mozilla Firefox\firefox.exe»

and child processes spawned by the main process have a Command Line like this:

«C:\Program Files\Mozilla Firefox\firefox.exe» -contentproc —channel=»numbers» .

What would be unusual is any URL specified, or any profile specified, etc.

Phoenix Shade [[#answer-1324644|said]]

And how do I see the parameters and what would be considered unusual?

There’s also a tool from Microsoft that shows a parent child relationship between processes which is sometimes handier:

I just did a reinstall after uninstalling using revo uninstaller. once installed, after a restart, this started happening again.

And how do I see the parameters and what would be considered unusual?

Add the Command Line column to your Details tab in the Windows Task Manager.

Normally, the main process Command Line looks like this:

«C:\Program Files\Mozilla Firefox\firefox.exe»

and child processes spawned by the main process have a Command Line like this:

«C:\Program Files\Mozilla Firefox\firefox.exe» -contentproc —channel=»numbers» .

What would be unusual is any URL specified, or any profile specified, etc.

It doesn’t seem unusual. The processes that start from running my current window of firefox and the problem process (the highlighted one) are quite similar. And I ran a full system scan with microsoft security, no problems were detected.

I don’t know if it’s relevant, but I recently upgraded to windows 10 2004. So, is it possible that it might be a factor?

Phoenix Shade [[#answer-1324644|said]]

And how do I see the parameters and what would be considered unusual?

Add the Command Line column to your Details tab in the Windows Task Manager. Normally, the main process Command Line looks like this: «C:\Program Files\Mozilla Firefox\firefox.exe» and child processes spawned by the main process have a Command Line like this: «C:\Program Files\Mozilla Firefox\firefox.exe» -contentproc —channel=»»numbers»» . What would be unusual is any URL specified, or any profile specified, etc.

So the one that says -headless is meant to be invisible to you and it uses -no-remote and -P «user» to avoid locking your regular profile.

Something in that user profile would be a clue to why it uses so much CPU. Maybe it’s just a little cryptomining for profit or maybe it’s something worse. However, it’s hard to describe how best and most safely to investigate that further.

I suggest renaming that user profile to see whether that makes it difficult for the unwanted process to start up. Here’s how:

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!)

Find the one that says:

Profile: user

and use its Rename button to hide it using, say, test instead.

Please also review your Scheduled Tasks for any startup task that has a similar command line.

Checking that command line a bit more, it seems to direct Firefox to connect to a subdomain under window-updates-service.com — sounds legit, but not really according to some Google results:

Wow, this seems to be more sinister what it appeared to be. I have the same problem as the guy in the reddit post but they just said that the website was quite cpu intensive, while your theory of cryptominers makes much more sense.

So, i changed the name of the profile «user» to «test». By next restart, the test profile was still there but another profile named user had popped up, with the process still going on in the background. The renaming didn’t stop it from starting.

As for the task scheduler, there is a task from what it says to be Mozilla, but after your lesson, I’m not so sure. It does seem suspicious that it starts up at 00:01 every day and in the conditions, it is said to retry if the scheduled startup time is missed.

So what should i do now? How do i get rid of that miner? And how did it get there in the first place, as i mostly use it for my college work and steam, so i don’t download stuff from outside.