Ask Leo!

Why does Firefox sometimes say it's already running when it's not?

Home » Web » Browsers » Firefox

Summary: Firefox can occasionally complain that it's already running when you might not see it anywhere on your desktop. It's not lying, it's just hiding.

I installed Firefox because IE7 just freezes up and runs really slow. So far I like it. It runs really fast, but every now and then I try to start it and get a message saying Firefox is already running and that I need to stop the program or restart my computer. I was wondering what you think I should or could do, plus I was just wondering what you think of Firefox.

I'm a big fan of Firefox, and I use it every day. I still occasionally run into websites that don't work properly in Firefox, but for the most part I rarely have to open Internet Explorer for my normal surfing.

But yes, I have run into the scenario that you've described. I'm always not sure what causes it, but I can show you what I do.

What I've seen when Firefox complains that it's already running is simply that it is already running, but it doesn't actually have any windows open. (One way to force this on purpose is to set a scheduled task that runs Firefox, and then log out of your computer and stay logged out while that task runs. At least that's how it happens to me.)

If you run task manager, or my favorite: process explorer, after getting this message you'll probably find that firefox.exe is indeed running:

Process Explorer fragment showing Firefox running

(In Task Manager you may need to make sure that "Show process from all users" is selected.)

If you find a Firefox.exe in the process list but don't see one running on your desktop, then you can right click on it and click on "End Process" (task manager) or "Kill Process" (process explorer). That should halt the unexpected Firefox and allow you to start a new copy that's visible.

An alternative for the command-line fans out there is the SysInternals utility called "pskill" which can be downloaded for free from Microsoft.

"... it is already running, but it doesn't actually have any windows open."

One you have the tool, then in a command shell you can enter the following command:

pskill firefox

That should result in something like this:

PsKill v1.10 - Terminates processes on local or remote systems
Copyright (C) 1999-2004 Mark Russinovich
Sysinternals - www.sysinternals.com

Process firefox killed.

If more than one copy of firefox was running, that would be terminated as well. In fact, any program with "firefox" in it's name would be killed. And of course if no such process exists it does nothing.

So rather than looking for and terminating firefox.exe in the task list, you can just use the command line tool to "kill 'em if you got 'em".

Related:

Article 12088 | Posted December 17, 2007

Recent Comments
8 Comments

All you have to do is hit''control-alt-delete', when box comes up ,you'll see firefox in the box, just highlight and hit end process, the firefox browser will be shut down, now click on icon for firefox and it will load.....

Posted by: JUMPSHOT at December 19, 2007 11:24 AM

I use FF all the time, and only run into this when I try to install a back-up copy of a profile into the "Profiles" folder. You cannot copy the entire folder - only the contents inside it (by pasting it). :)

Posted by: Carl R. Goodwin at December 21, 2007 6:27 PM

My problem is that after I've put my computer into Stand By mode (where it actually shuts off and comes back to the same spot once you restart your computer), my firefox won't restart properly no matter how many times I follow this procedure. I need to ensure that I don't close my firefox when I put the computer into Stand By mode.

Posted by: Peter Woerner at December 22, 2007 5:04 AM

I've had this problem on and off,where programs would not open up, yet in the task manager, it indicated they where open in the background.

Not just with Firefox. I do have it on my system but my browser choice is Opera, and I've had it happen with it. There was no error message, it just wouldn't open, except in the background, according to task manager.

My sister called recently and had a similar problem with Windows Live Messenger. And then another guy called me with the same problem. I first opened task manager by right clicking on the task bar and chosing it from the menue. Closed all instances of Messenger (there would be about a half a dozen or so where they tried to get it to run). Then to the 'control panel', double-clicked on 'Add/Remove programs', clicked on the list item for 'Windows Live Messenger', there where two options, 'change or uninstall', clicking on the change button will give you two options, to 'repair' or 'uninstall', I choose 'repair'. It seemed to work temperarily. I eventually uninstalled and reinstalled. So far so good.

And to top it all off, I still cannot run the newest versions of Adaware 2007 or Spybot 1.5, I still have to use the old versions. I just keep checking and downloading the newest version occassionally, maybe one of them will work one day.

Terry Hollett
www.geocities.com/terryhollett2003/

Posted by: Terry Hollett at December 22, 2007 6:51 AM

i use a school mac and i always get "firefox is already running" error im new to macs and the school admins are baffled any ideas on how to view processes on a mac running osx

Posted by: concerned student at March 13, 2008 11:54 AM

There's no reason to use IE even on sites that arent supported by Firefox. Just download IE tab extension. It emulates IE in Firefox. You can download it from here: https://addons.mozilla.org/en-US/firefox/addon/1419

SFC doesn't run "on a drive", it runs on your system. That means it checks the Windows installation in use wherevere it might have been installed.

-Leo

Posted by: Anonymous at August 4, 2008 11:31 AM

I use FF all the time, and only run into this when I try to install a back-up copy of a profile into the "Profiles" folder. You cannot copy the entire folder - only the contents inside it (by pasting it). :)

Posted by: Carl R. Goodwin at December 21, 2007 06:27 PM


You sir, saved me about 30 minutes of headache. Old post, new info. Thanks.

Posted by: Michael at September 12, 2008 5:42 PM

I am having the same problem, only firefox.exe is NOT in my task manager...what do I do ??

Use process explorer (http://ask-leo.com/d-procexp) - it shows processes that Task Manager by default does not.
- Leo
22-Oct-2008

Posted by: Chris at October 21, 2008 12:57 PM

Post a comment on "Why does Firefox sometimes say it's already running when it's not?":






(Email Address will not be published.)

Remember Me?

By popular demand...
my tip jar
Cuppa Joe
Buy Leo a Latte!

(you may use HTML tags for style)

New!

RSS feed Subscribe to the RSS Feed specifically for comments on this article.

Before commenting, please...

Please wait. Your comment is being processed ...


Ask Your Question:


ask-leo.com
Web

Stay Informed

Weekly Newsletter

Archives

By Category
By Date

Advertisers

Advertise on Ask Leo!

««   »»

Question? - Ask Leo!
Who is Leo?
Link to Leo!

Terms, Conditions & Privacy