Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Lolu chungechunge lwabekwa kunqolobane. Uyacelwa ubuze umbuzo omusha uma udinga usizo.

FF 29 sometimes will not start. Popup with an error message.

  • 68 uphendule
  • 220 zinale nkinga
  • Igcine ukuphendulwa ngu John99

more options


With FF 29, I frequently get a popup message saying that "Firefox is already running" and I have to kill that process and restart the browser under XP. Is anyone else experiencing this problem?


Isisombululo esikhethiwe


Note one potential fix is now in the very recent Firefox Beta 30b8 Initial reports suggest this fixes the issue. (Bug1005487#c38) If you have been suffering from this problem and want a fix now instead of in a few weeks time you may wish to download and install the Beta version of Firefox.

The beta version is effectively a release candidate but is only intended for advanced users or testers. I would be interested to hear feedback from those of you that do test this out.

Beta version download

Funda le mpendulo ngokuhambisana nalesi sihloko 👍 0

All Replies (20)

more options

Hi again Compumind

What would be helpful is if we can get formal Steps To Reproduce.

This bug would not even exist if it happened on everyone's computer. Obviously it does not. Something is different.

One problem is we have identified one potential cause, so we now need to separate that bug out and concentrate on those with a similar symptom but a different bug.

I posted the following in /questions/997918?page=2#answer-568336

We really need help from the guys that see this problem to get proper STR.

IMHO STR that are described from

  • Using a new clean profile.
  • All Plugins disabled.
  • Starting in Firefox's safe mode.
  • (edit - additional note Use only about:blank have no other tabs open. )
  • Trying to exit into safe mode, by using the safe mode restart option,
    New Fx Menu -> Help-29 ->restart with addons disabled...
    Does that hang ?
  • Exiting using the new closedown button
    - that should hang as the test for this.
    New Fx Menu -> Help-29 -> close 29~J99

Of course if you cannot do the above and make firefox hang then you have a workaround that solves your problem.

  • Compare that to your ordinary install and ordinary profile, what are the differences ?
  • Write STR, others will try to reproduce.

Basicly someonewho sees the problemneeds to effectivly startfromscratch with Fierfoxsoit is adefaultconfiguration.

Then test and prove Firefox 29 works ok without hanging.

Compumind Are you and others who see the problem able to get to that stage where Firefox 29 works ?

Now make minimal changes maybe open one internet site in the blank tab and logon. At this stage Firefox will be expected to work. Now one thing at time change something until the problem can be seen.

I think most people seeing the problem are coming from the opposite direction. People are doing one of two things

  1. They may change a single pref and it works.
    Good that is a clue as to what is happening.
    • Toggling the value of the pref "network.seer.enabled" gives us a good clue to one problem area. Something that did change in Fx29
  2. They use Fx28 and it works. They use Fx29 and it fails, revertingto Fx28 and all is ok again.
    Again a good clue.
    What we need to know is how to get to the stage where the problem occurs, because only some people see the problem.

At first thought it is simple, something changed in between Fx28 & Fx29. But how can anyone test that if they themselves can not make the problem happen.

Once someone can make the problem happen we can start tracking it down. There were quite a few cahnges between Firefox 29 & Fx28 just glance at this listing

  • Nearly 4000 changes

The steps I listed above are fairly standard,but each one probably needs explaining. I will make a follow up post and expand the steps.

With STR if it is not obvious what causes the bug there is a utility that will narrow down the range of changes and tell us fairly accurately which changes are likely to be the problem so only a sub-set of the nearly 4000 changes needs to be scrutinised.

more options

I will expand on the suggested starting point for STR

IMHO STR that are described from

  • Using a new clean profile.
  • All Plugins disabled.
  • Starting in Firefox's safe mode.
  • Use only about:blank have no other tabs open.
  • Trying to exit into safe mode, by using the safe mode restart option,
    New Fx Menu -> Help-29 ->restart with addons disabled...
    Does that hang ?
  • Exiting using the new closedown button
    - that should hang as the test for this.
    New Fx Menu -> Help-29 -> close 29~J99

Using a new clean profile.
Create a new profile. Use an empty folder. The easiest method to create a new profile is to use the built in profile manager

All Plugins disabled.
Use about:addons and disable all plugins.
Key into the location bar about:addons Select each of the plugins in turn and set as never activate.

Note Firefox's safe mode does not disable plugins

Starting in Firefox's safe mode

Use only about:blank have no other tabs open. Close all tabs except one blank tab. Keying into the adddressbar about:blank and hitting Return.

more options

Your advice is most unhelpful! I created a new profile, but this lost all my bookmarks etc. I have reverted to 28 and you obviously have a problem with 29 which you need to sort out, quickly. If note - Chrome!

more options


Thanks for the revised steps. :)

I tried all of them on another XP machine which never had FF on it.

Just used a default install of FF 29.

Result was the same (negative) - same error message as above.

How about other people here who have this problem?

It would be great if they also followed the procedure and posted their results. Seems that many others have the same/similar issue but just click the button about having a "me too" issue, which doesn't really help.

From what I gather this problem affects Windows XP and 7.

Good luck.

Okulungisiwe ngu Compumind

more options

Hi jenoseeel,

  • Short answer

Please Ask Your Own Question, and note that the original bookmarks should be seen if you open Firefox using the profile manager to start it with the original profile, and that if you ensure firefox does not clear Cookies or History on closedown it should work without hanging.

Longer answer
(Points numbered to make it easier to refer to not as a sequence of steps)

  1. Your original profile should still be there with the original bookmarks, open that profile with the profile manager and you will have the bookmarks still.
  2. These are intended as troubleshooting steps and may not solve the problem. But they should give you a workaround.
  3. Quite possibly setting Firefox to NOT clear History or Cookies when closing WILL solve your immediate problem.
  4. If you need help,as you appear to please start your own question, PLEASE use this special link, it is quicker and will be recognised by contributors as relating to this thread.
    1. Special Link for questions on this problem of Firefox 29 won't start, hangs when History is cleared on closedown.
    2. Please ensure you follow the prompts to include full troubleshooting information when you post your question
    3. Please mention in this thread of Compumind's when you have started your own question. Others may wish to follow the progress and help you.

Sorry you are having problems and find the advice unhelpful.

The suggestion was intended to be for troubleshooting and creation of a new additional test profile. if you did follow those steps you would still have the original profile and that will still have your bookmarks and can easily be selected and used as normal from the profile manager.

  • For longer notes and more information on profile particularly using multiple profiles use have a look at a previous post I made [/questions/990973#answer-548376]

There does seem to be a genuine problem with Firefox 29, and as it is locking people out of Firefox it does need fixing as a high priority. What you will not realise is that it does not affect everyone. Possibly it only affects a fraction of a percentage of Firefox users. That is still going to be Millions of people but we need to find one of those Millions that is able to show us what we need to do so that we can see the problem. That's what we call STR which is short for Steps To Reproduce.

  • And should you be interested in why they are required this is an easy to read article with no technical jargon in it mentioning why some problems are hard to find.

Compumind was asking what sort of information would help us in seeing the problem, I am trying to answer that.

Okulungisiwe ngu John99

more options


Just to clarify,

My problem occurs when starting up FF 29, not on browser shutdown.

Have to kill the FF process and restart the browser.

Cookies and History are not cleared - problem still occurs.

Cookies and History are cleared - problem still occurs.


Okulungisiwe ngu Compumind

more options

Yes I realise you see a problem on Firefox starting up. However that problem appears to be because Firefox is not shutting down properly. It is hanging as it shuts down. That is why you see a process still running and are needing to kill the process before you can use Firefox.

You can not start up Firefox whilst the original process is still trying to run and has locked the profile. If you tried to start Firefox with an alternative profile it would startup ok, if you used the -no-remote argument

more options

You are missing the point; I am not a 'techie' and just want a programme that works properly. You wouldn't buy a car where you had to fiddle under the bonnet each time you tried to start it - would you! In the meantime V28 works perfectly before you decided to 'improve' it and if that becomes too prone to security problems then Chrome it is.

more options

I agree Firefox29 should work for you and it is not doing so at the moment. Yes you would be better off using Chrome because it can not be recommended that you continue using an un supported and insecure Firefox 28.

Probably all you need to do to be able to use Firefox 29 is to set Firefox to its default and to NOT clear history and cookies at closedown.

This issue is something that needs priority attention, but I personally have not yet succeeded with STR and I have not yet noticed anyone else doing so fully where others agree they can replicate.

I will have long since tagged this question as escalate but see no respnse yet from HelpDesk staff. They will have been very busy with other Fx29 questions. I will try untagging the question then retag it in a few hours, I imagine that will ping the HelpDesk again and so keep it on their list of questions needing attention.

more options

Worked a couple of times and then same error message came up. Had to re-boot computer to be able to use Firefox again.

more options


For Your Information.

Firefox update to Firefox 29.0.1 One of the changes is a workaround for some of the issues with Firefox hanging. ( It is effectively changing the seer pref.)

After that change we will be able to concentrate more on the outstanding cases, and get bugs filed if possible.

Just as an aside I do not think I have yet-mentioned in this thread it may be a good idea to turn on telemetry this passes anonymised data to Mozilla, in accordance with the Privacy policy. Aggregated data is then made available publicly. Analysis of the data helps developers see problems. It for instance shows the startup time. (Not sure how it copes where Firefox does not start, but it would not surprise me if it also reports Firefox hangs)

  • Share data with Mozilla to help improve Firefox
    • 'about:telemetry shows your own data
    • Mine under Browser Hangs shows (No data collected)
      I presume that is not an indication that telemetry is faulty, but because I have not had browser hangs.

Note you can also see your own personal data, as kept on your own computer; without you submit anything to Mozilla by using Firefox Health Report. The data is probably totally meaningless to most people. I am not certain what most of the datasets are but if you want to see the pretty graphics it is available to you.

I have added the tag escalate to this thread again. I removed it a few hours ago in an attempt to bump this thread for HelpDesk staff.

more options


Thanks for the post :)

I see that the update has not been pushed out yet. When do you think?


more options


Firefox's 29.0.1 update will be released tomorrow. After 29.0.1 is released, Mozilla will start pushing automatic updates to 29.

John99 does that sound correct?

Okulungisiwe ngu Moses

more options

Last I heard they were expecting it to be appearing from 9am Pacific time Friday.

more options


Just updated to 29.0.1

Unfortunately, the problem remains.


more options



First, I presume you understand I, like others here, spelled out my response in enough detail to allow others to do what I did. I can tell you did not need anything more than being told to try a clean install with another profile and set it up so you can run multiple copies of FF.

Second, I should have started that earlier response by copying the beginning of your continuation thread referencing by Compumind and using part of your words, saying, "[I am] having the same experience, [ I keep getting the "Firefox is already running message.] [but only] when opening links from emails in Thunderbird." but I can possibly help you with the clear history and bookmark issue.


It was through the "Firefox already running" problem that I found your issue with Clear History hang and the bookmarkbackup issue. I wasn't clear that I was indeed addressing those two latter issues. As I have been upgrading I have been experiencing more and more slowing of the browser, but didn't see it on other computers of mine or those I set up for my wife (she gets a different computer from work each year, so gets a clean install and transfer of profile each year). I presume this clean install cleared that up because I have no hangs and speed.

'Before responding to you, I did try and could not replicate the hang when clearing history on exit and had no problem with bookmarks. From the time stamp, the places.sqlite and the places.sqlite-wal files change immediately on bookmarking, while the bookmarkbackups.json file modifies about every 25 hours. Letting the computer sit idle had no detrimental effect or otherwise. When I open the bookmarks, all new bookmarks are available. Closing browser and clearing history on exit caused no noticeable lag or hang. I replaced the history with a backup file several times and had no effect.

I hate to have to do a clean install (I hadn't done one on the computer I am referring to since FF2 until FF29Beta), but it resolved many issues I was having. There are also many less unneeded files in the profile. If you do a clean install, please let us know the results. However, as I see it, do expect the "Firefox already running" problem to remain for now. That is a minor issue to me compared with the hanging and unreliable bookmarking others are experiencing.

Other than the Firefox is already running issue, I have seen no problems with FF29 aside from the UI changes that are not really desirable such as why the need for an extension to move stop / reload and back / forward buttons off the url bar; keeping the non-intuitive and reworked FindBar from an earlier version, that simply caused me to change it back using userchrome.css. Also, very important, trying to make it easier to customize removed some ability to customize. I use All-in-one-sidebar, a common AddOn, but the new Customize in FF does not let you move buttons to the sidebar's toolbar (at least, I haven't figured out a workaround yet). But, I agree, FF is the best because it is so customizable. STOP taking that customizability away.

more options


Just updated to 29.0.1
Unfortunately, the problem remains. 

That was to be expected in your case. The fix may help some people that is why it was pushed.

I say it was expected in your case because when asked about the effect of toggling network.seer.enabled to false you replied (upthread) that it did not help.

I was rather hoping you may be able to have a go at the STR yourself. This thread is getting a bit long and confusing but I was asking earlier if you could get Firefox to the state where it did NOT hang.

See this post of mine upthread link
Where after explaining how to make a start on a STR attempt I said

Compumind Are you and others who see the problem able to get to that stage where Firefox 29 works ? 

Now make minimal changes maybe open one internet site in the blank tab and logon. At this stage Firefox will be expected to work. Now one thing at time change something until the problem can be seen.
more options


As mentioned in one of my previous posts, I installed FF 29 on another XP system which did not have FF previously installed. When I did the install on that machine, no add-ons or plug-ins were installed except by default.

I also updated that same machine today with 29.0.1 - same situation.

Perhaps it has something to do with XP in a certain configuration.

Unfortunately, I just don't have the time to tweak for Mozilla.

I also see that nobody else had posted data, so I'm done, lol!

Many thanks for your assistance!


more options

I have updated and the problem still exists. As a strictly non-'techie' I do not expect to have to try to tinker with a programme to corrects it's faults. I am running an up-to-date version of W7.

more options

Hi Compumind,

I will just try to sumarise the current situation.

OK I understand you are not wishing to waste time on this. I have noted some others are finding STR on similar problems. All of course start from a working Firefox 29.

I guess so far you have been unable to get Firefox 29 to work other than using Firefox portable. By now you will have used a clean profile. And will have used a clean reinstall of Firefox. I hope when trying that you are remembering NOT to set Firefox to forget History. By default Firefox will remember History on closedown.

You could have a different issue to some other people. You were speculating this could be an XP related issue. I note you are expecting to change the XP machines shortly. Meanwhile trying XP's safe mode with Networking, would be worth trying.

You can ignore this just me thinking aloud about progress on similar issues.

Apparently these STR have been verified by some
From Bug 1005958 - Disable seer until new backend is rewritten #c24

We managed to reproduce it by setting the pref [1] privacy.sanitize.sanitizeOnShutdown to true or by selecting [2] "Clear history when Firefox closes" option in Firefox Preferences. In each case, the STR are the same:
1. Set the above pref (either [1] or [2])
2. Restart browser
3. Load 3-4 full HD videos from Youtube
4. Wait a few minutes
5. Close Firefox

Results: The Firefox process is not closed.
Reproducible also on Firefox 29.0.1.

Possibly a related bug now is
Bug 1008148 - Use AsyncShutdown for PageThumbsStorage.wipe()

To clarify, PageThumbsStorage.wipe() may be called on shutdown with "Clear History when Firefox closes" enabled.
  1. 1
  2. 2
  3. 3
  4. 4