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Firefox 29 fails to exit properly and remains running in task manager.

  • 42 replies
  • 206 have this problem
  • Last reply by John99

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This is a continuation of a thread found here: by Compumind.

I reported I was having the same experience, especially when opening links from emails in Thunderbird. I also reported I was forced to revert to FF 28.

Moses replied in above thread and suggested: (1) Download a fresh installer from to a convenient location. (Scroll down to your preferred language.)

(2) Exit out of Firefox.

(3) Rename the folder

C:\Program Files (x86)\Mozilla Firefox


C:\Program Files (x86)\OldFirefox

(4) Run the installer you downloaded in #1. It should automatically connect to your existing settings.

I followed these instruction carefully but no joy. Upon installing FF 29, not only would it refuse to exit (using "exit") and remain running in the Task Manager until I killed it after opening links from Thunderbird, but I found it refused to exit after simple browsing and following links.

Moses had asked I not reply in original thread so I am re-posting here.

I believe this is a serious bug. With Firefox problems except a minor one I reported here:

Again I am forced back to FF 28, though I miss the beautiful interface and security fixes, I need to have a browser that works properly. My wife has never even seen the Task Manager before so this is problem.

Besides the "educated guesses" made with this post, the only other thing outside of usual that I do, is to have a security policy regarding cookies (don't accept by default...I make exceptions for cookies I want to retain and have a several that are only "allow for session.") I also have FF set to delete browsing history on exit, but that takes a split second.

I look forward to when this issue can be addressed successfully and I am able to use FF 29 (and have it exit properly...I can't expect my wife to follow all these instructions and close it often manually in the task manager...nor do I want to do this.)

Good luck on all the Mozilla projects. Having installed FF 29 twice and then reverted back to 28 twice, I am going to wait and see how this plays out. Please don't send me the standard, "start in safe mode", "restart with add-ons disabled", "reset Firefox" (last time that destroyed my browser completely) stuff. I do not believe this is what's happening.

Moses added that there is a problem with email notifications going through, so take your time, friends.

Modified by Axis

Chosen solution

I now (temporarily) believe this bug or issue has its roots in the "Clearing of History on Exit" setting.

I took the plunge after some further playing around with the PortableFirefox 29 and reading the blog post linked here:


...and installed FF 29 over my previous FF28 on my box. I have unchecked the "Clear History on Exit" which was only deleting my history, not cookies or anything else, cor-el. My setting are not to accept cookies unless I make an exception. Until the FF developers find a way to make this functional, I will have to simply delete history manually.

By the way, John99, you would want privacy.sanitize.sanitizeOnShutdown set to "False", not "True" if you want to stop the automatic (attempt) at deletion of history on exit.

I have been running for about 6 hrs. without experiencing the "hanging" bug. So I can live with that for now until this bug is fixed. It should be fixed...browsers are supposed to be able to do things like that.

On the other hand, I might find things go bad...but so far I am not having a problem.

I have been running for several hours and will let you know later whether things change.

Kind Regards,


Read this answer in context 👍 12

All Replies (20)

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Hi Axis,

Thanks for creating a new thread. My problems were actually related to my e-mail address. :/ Should be working now. :)
Note: A list of troubleshooting to try is coming!

Please don't send me the standard, "start in safe mode", "restart with add-ons disabled", "reset Firefox" (last time that destroyed my browser completely) stuff. I do not believe this is what's happening.

Well it looks like I'm going to do what you said not to do and ask you to Start in Safe Mode since this is a good thing to rule out. On some occasions, a faulty extension or conflicting one is causing a problem. Firefox can hang if it's due to a faulty extension.

Can you try to start Firefox in Safe Mode to see if Firefox works properly with no error? You can start Firefox in Safe Mode below:

  • Windows/Mac: Go to Help > Restart with add-ons disabled
  • Linux: Run firefox -safe-mode in the Terminal/Konsole

One possible extension that could be causing this is Skype-Click-To-Call If Firefox opens up fine with no problems, it's probably one of your extensions that's causing the issue. You can re-enable your add-ons one by one until you find the one that causes the issue upon being re-enabled.

There's probably something wrong with your Firefox setup. Your System Details looks very light/empty. Can you start by giving us the troubleshooting information from the Firefox installation that's having problems. This is an essential step in troubleshooting.

  • Click the Firefox button at the top left, then click the Help menu and select Troubleshooting Information from the sub-menu. If you don't have a Firefox button, click the Help menu at the top and select Troubleshooting Information from the menu.

Now, a new tab containing your troubleshooting information should open.

  • At the top of the page, you should see a button that says "Copy text to clipboard". Click it.
  • Now, go back to your forum post and click inside the reply box. Press Ctrl+V to paste all the information you copied into the forum post.

Please be sure to keep all of your plugins up to date:

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Hello Moses--

My plugins are all up to date. I check first thing every day. I only have three, well 4 if you include WAT: Shockwave Flash 13.0 r0 Adobe Shockwave for Director Netscape plug-in, version 12.1 Adobe PDF Plug-In For Firefox and Netscape 11.0.06 Windows Activation Technologies Plugin for Mozilla.

I only have one extension: FireBug 1.12.8 and I am not ordinarily using it except in my web development "safe mode" won't help.

I will give you the "more information" minus the million ancient printer details. But I have already reverted back to 28, again, and unless you see something I can fix, or find a bug, I don't feel like doing it a third time. The "user.js" is a simple addition to I can copy and paste into a TinyMCE JavaScript editor on one of my websites and only says:

user_pref("capability.policy.policynames", "allowclipboard"); user_pref("capability.policy.allowclipboard.sites", ""); user_pref("capability.policy.allowclipboard.Clipboard.cutcopy", "allAccess"); user_pref("capability.policy.allowclipboard.Clipboard.paste", "allAccess");

I will say thank you for looking, Moses. I hope I don't seem hard-nosed about not wanting to going around and around in circles, but I am waiting for some new information before I download FF 29 again. I have done this (asking questions) a million times and kind of know how these things play through.

Kind Regards, Axis

Application Basics

Name: Firefox Version: 28.0 User Agent: Mozilla/5.0 (Windows NT 6.1; rv:28.0) Gecko/20100101 Firefox/28.0

Crash Reports for the Last 3 Days

All Crash Reports


Name: Firebug Version: 1.12.8 Enabled: true ID:

Important Modified Preferences

accessibility.typeaheadfind.flashBar: 0 browser.cache.disk.capacity: 51200 browser.cache.disk.smart_size.enabled: false browser.cache.disk.smart_size.first_run: false browser.cache.disk.smart_size.use_old_max: false browser.cache.disk.smart_size_cached_value: 358400 browser.places.smartBookmarksVersion: 6 false true browser.sessionstore.upgradeBackup.latestBuildID: 20140314220517 browser.startup.homepage: browser.startup.homepage_override.buildID: 20140314220517 browser.startup.homepage_override.mstone: 28.0 browser.tabs.loadInBackground: false browser.urlbar.autocomplete.enabled: false dom.mozApps.used: true dom.w3c_touch_events.expose: false extensions.lastAppVersion: 28.0 font.internaluseonly.changed: true general.autoScroll: false gfx.direct3d.last_used_feature_level_idx: 1 keyword.URL: network.cookie.cookieBehavior: 2 network.cookie.lifetimePolicy: 1 network.cookie.prefsMigrated: true places.database.lastMaintenance: 1398912020 places.history.expiration.transient_current_max_pages: 80511 plugin.disable_full_page_plugin_for_types: application/vnd.fdf,application/vnd.adobe.xdp+xml,application/vnd.adobe.xfdf plugin.importedState: true plugin.state.npdeployjava: 0 plugin.state.npgoogleupdate: 0 print.printer_HP_DeskJet_710C_(Copy_1).print_bgcolor: false ...and on and on about the printer... privacy.clearOnShutdown.cache: false privacy.clearOnShutdown.cookies: false privacy.clearOnShutdown.formdata: false privacy.clearOnShutdown.offlineApps: true privacy.clearOnShutdown.sessions: false privacy.sanitize.migrateFx3Prefs: true privacy.sanitize.sanitizeOnShutdown: true security.disable_button.openCertManager: false security.disable_button.openDeviceManager: false security.warn_viewing_mixed: false storage.vacuum.last.index: 1 storage.vacuum.last.places.sqlite: 1396579220

user.js Preferences

Your profile folder contains a user.js file, which includes preferences that were not created by Firefox.


Adapter Description: NVIDIA GeForce 9400 GT Adapter Drivers: nvd3dum nvwgf2um,nvwgf2um Adapter RAM: 1024 ClearType Parameters: Gamma: 2200 Pixel Structure: B ClearType Level: 50 Enhanced Contrast: 300 Device ID: 0x0641 Direct2D Enabled: true DirectWrite Enabled: true (6.2.9200.16571) Driver Date: 12-19-2013 Driver Version: GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 10 Vendor ID: 0x10de WebGL Renderer: Google Inc. -- ANGLE (NVIDIA GeForce 9400 GT Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote: false AzureCanvasBackend: direct2d AzureContentBackend: direct2d AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0


Incremental GC: true


Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.3 Version in use: 4.10.3

NSS Expected minimum version: 3.15.5 Basic ECC Version in use: 3.15.5 Basic ECC

NSSSMIME Expected minimum version: 3.15.5 Basic ECC Version in use: 3.15.5 Basic ECC

NSSSSL Expected minimum version: 3.15.5 Basic ECC Version in use: 3.15.5 Basic ECC

NSSUTIL Expected minimum version: 3.15.5 Version in use: 3.15.5

Again thanks and kind regards, Axis

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The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information.
Note: This will cause you to lose any Extensions and some Preferences.

  • Open websites will not be saved in Firefox versions lower than 25.

To Reset Firefox do the following:

  1. Go to Firefox > Help > Troubleshooting Information.
  2. Click the "Reset Firefox" button.
  3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
  4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Thank you.

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I should add that FF 29 remains running in the Task Manager processes tab and not the application tab.

Debapriya Bhattacharya--thank you...but I have no intention of losing "some of my preferences", which would include, I assume, all my cookie settings and exceptions. I need my browser to work every day for the work I do. I can't do my work without a I can't spend a week "debugging" this.

I have spent years trying to get Windows 7 to do what I want, not just what Windows wants...though I respect a need for balanced operation. And I have spent the time between FF 18 to FF 29 making my browser, Firefox, do what I want it to do. This is one of the things Firefox has been so good at, user control. I use a "lightweight theme" I created myself, I set cookie policies and exceptions so I could have security and functionality. I have nothing but the most basic add-ons, much less than most. It is like you are building a house and you spend much time getting it just the way you like it and need it...and working properly.

I got creamed once before way back in FF 17 or something when I upgraded and a "bug" in Firefox deleted all the permissions I had set. I had to revert to a version way earlier and then, when permissions finally worked, I began to rebuild EVERYTHING from the ground up. I took me a week and I was about to throw FF away...but I love Mozilla and what it stands for so I will stay "here" at 28 until enough people report this problem for someone to look deeper into it.

You see, people on the support forums always believe it is some misguided or ill informed user mistake, and sometimes it is...but it is not always so. I think there is a coding conflict and not something wrong with the settings above which I added upon request...or do you see something there? Everything "works" now with 28, as it worked with FF 18-29, and it should work in 29, but it doesn't.

Kind Regards,


Modified by Axis

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According to this thread at this time:

15 now have this problem. Combined with this thread (7 people at this thread now have this problem. That's 22.

Regards, Axis

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Debapriya Bhattacharya--

I actually spend the best part of the day fooling with things and following your instructions after re-installing FF 29:

   Go to Firefox > Help > Troubleshooting Information.
   Click the "Reset Firefox" button.
   Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
   Firefox will open with all factory defaults applied. 

I thought I had it, but on further testing FF started to "fail to exit and remain running in task manager."

Back to 28 again.

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Coming from a PC technician perspective when is the last time you had your computer re-imaged i.e. how old is your Windows 7 operating system? There are many variables at play here and in my personal experience as a PC tech I find that a simple re-installation of Windows fixes countless complex software problems. I've had this bug before on the same computer I'm typing this response on and since I re-imaged it I haven't had an issue. Sometimes copies of Windows become corrupt and decide to stop working altogether since it such a complicated piece of code. My recommendations are:

1) back up all your important files to an external hard drive or flash drive depending on how much data you need to backup

2) re-image your computer with a clean installation of Windows 7

3) Install Firefox 29

As it goes in the world of information technology I can't guarantee a 100% fix but I re-image 8 year old computers with a fresh copy of Windows 7 on a daily basis for with the latest version of Firefox for my job and it (mostly) turns out fine unless there is a hardware issue that needs to be addressed but I don't think that is the case here.

This all seems very drastic I'm sure but you can wait for a patch to see if it fixes it if you believe that will help or just keep your installation of Firefox 28

Modified by cryptochange

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I have no intention of re-installing windows. Yes I am keeping 28 until a patch or fix for this occurs. Just had an update from windows for IE 10. It is not my operating system, if it was I would have more problems than FF 29.

28 works fine, as it always has. I spent the better part of the day following useless advise, resetting FF 29, finally getting my setting back the way I want. Now you want me to re-install Windows?

I am sorry for being snarky, but a browser should not be an issue that requires so many "drastic" solutions. If Windows was a problem, I would know it. The bottom line is since FF 28 works perfectly, and 29 refuses to exit properly then it is a Firefox problem and someone should address that issue and not tell the 23 people who have this problem at this time in this thread, and the 32 people who have this problem in this thread: to re-install Windows, for heavens sake.

My "box" is a server as well as my PC. I'll wait until the FF developers fix the Firefox problem, and quit offering useless advise to insult intended. I know you are doing damage control here.



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Hi Axis,

Sorry for the long wait. There's a ton of question and a ton of multitasking going on.

If anything is going on with your current setup of Firefox, a new profile will knock the hell out of whatever is going on.

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

See "Creating a profile":

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

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I'm sorry that my advice was of no use to you Axis. For clarification purposes yes I understood that 55 other people have the same issue and in my line of work 55 computers in need of a re-image doesn't sound that drastic or unorthodox. That's 55 different computers with 55 different copies of windows, programs, and Firefox extensions (and in your case a dual purpose server personal computer running many many things) experiencing a problem that can have multiple vague causes. I just happen to know it can be fixed with a simple re-image. Moses has a great suggestion though that I didn't even think of. Let us know how it works out :)

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I already did that when I did the "reset Firefox" (and destroy your browser) thing. That gave me a new profile, alright, but by the time I put things back together...same joy.

The page lists "preferences" as a common "problem." Well preferences are extremely important to me, and the heart of what makes FF outstanding, and I need my cookie policy to work.

Truly, I have spent almost 36 hours since this began doing everything possible to fix, or at least debug this issue. First (if I can recall it all sequentially) there was a Flash Update, which I did. Then I saw there was a new version of Firefox, which I did. Then there was a new version of Thunderbird, which I did.

I am telling you this is a coding bug in 29. I mentioned on the other thread today (where you told me to start a new thread--this thread) that my wife has a shop at Etsy and it was the talk of the forums, there, that people were having a "terrible time" with "the new Firefox."

You can't just judge how widespread this is by counting up the (now) 29 "I have this problem also" on this thread and the 42 on the other thread. I did a search here yesterday for "Firefox 29 fails to exit properly" and it took me forever to find this and the other thread where I began.

Sorry, I am sticking to FF 28 until someone realizes there is a bug...actually 2 bugs, FF 29 also failed to create it's daily bookmarks backup...but this issue is more critical in my opinion.

I am going to quit receiving all these emails (but I will keep checking this tread in my bookmarks) because it has got to the point where we're going around in circles. I check everyday my plugins, and also Firefox releases so when I see a new one, I'll give it a try.

I thank you and all for your advise and attempts to help.

One final note on the behavior of this bug. When you first install the 29 version everything seems fine. After you have run it a while, that is when the "bug" shows up. I see it most noticeably when opening links that come in emails (Thunderbird). Last night, after doing the "reset and destroy your browser" option (which gave me a new profile) and surfing around trying to rebuild some of my cache I sent my self an email with links. I started opening them one by one and then exiting (not just "closing") 29 and the first 4 or 5 worked fine. After that they began to fail almost continuously. I downgraded to 28 (thankfully I had a backup of my profile but I had to change the profile.ini to go back to my old profile) and then ran the same test with a email full of links and did the same test. No problems at all with exiting Firefox, or it hanging in the Task Manager.

I love Firefox and Mozilla, but I had this happen once before as I mentioned somewhere (back in version 17? maybe), where my permissions were not working anymore...I do run tight permissions as far as cookies and exceptions...and had to start with some way earlier version and find one that would retain settings, then upgrade step by step to the current version (at the time) and have had no further issues with upgrades until now. I also had Chrome at the time and it wasn't having problems so I had something to fall back on. Now I won't touch Chrome with a 10 foot pole.

Again, thanks, Moses, and all. But I will wait for a "fixed version." Maybe if I did a complete uninstall of Firefox and then downloaded 29 it it would work but I would have to slowly build everything back again and I am not willing to do this. I need my browser to work every day and an upgrade over a "working fine" browser shouldn't be (and usually isn't) a huge disaster.

Kind Regards,


Modified by Axis

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Hi Axia,

It is probably a combination of the clearing history & your plugins.

That's why in the other thread you posted in I suggested all the troubleshooting steps together. But now all you need to try is

  • Disable the plugins from about:addons
  • Set the cookies and History clearing back to defaults.
    Specifically and best to check in about:config ensure you set to True False privacy.sanitize.sanitizeOnShutdown

For future reference

  • The method as suggested by Moses of creating an new additional profile can make more sense than the Reset.
  • Note Firefox SafeMode does not disable plugins or reset prefs.

Refresh Firefox - reset add-ons and settings

Daily bookmark backups.

I am surmising that because you are hanging on exit and possibly killing Firefox processes that will be the cause of the bookmark backup failure.

Modified by John99

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Updated Information.

I have taken the liberty of copying the post from the other thread.

john99-- I apologize for my venting earlier.

O.K, I am here with a new Portable FF 29. I want to tell you what I have done and the settings and files I added, etc. in an attempt to debug this whole problem.

Besides what got migrated "by itself" when I installed PortableFirefox on my zip drive, where it seems "self contained", after a little clean-up, the first thing I did was go into options and set 29 not to accept cookies (though it had imported the ones I had). I moved two files: permissions.sqlite and cookies.sqlite into the Data/Profile folder. I also added a simple self made theme found here; [] .

I set 29 to a cache of 50MG and set it to Custom settings for History; remember my browsing and download history, clear history when FF closes, set only for browsing and download history and offline website data. I also imported my bookmarks.

That was enough to run the test. Same as I mentioned somewhere in this or another thread, I sent my self an email in Thunderbird containing a list of links. About the 4th link came the error pop-up that Firefox was already running...this whole problem.

You mentioned deleting cookies and history on closing could be problematic. Well I am not deleting cookies, but I am deleting history. Every other browser can do this...but I have the feeling this is the snag with 29. I could be wrong, however, if that is the snag then it is very weird because read through the whole debate at [] where Marco Bonardo steadfastly holds to his position that "it is all a fake sense of security", while I find the comment by al_9x discussing the issue with him; "You have removed functionality that people use and like, that's been in Fx from its inception. It is you who need to justify its removal. And your justification of "nobody really wants to expire history" is a lie, people do and I explained why."

Then Marco Bonardo writes a plugin to do just that! []

In my case, running the plugin with the huge history I had, crashed my browser, deleted my cache and many bookmarks. At that time I just had to delete places.sqlite and set history as it is above--delete on exit.

So if this is a bug, or "buggy behavior" as a euphemism, then it is a real double bind situation. They took away that history option and I read above: "Clearing history & cookies on shutdown has been known to cause problems in the past."

Right now, it sure explains a lot...if this "issue" is affecting people who are deleting history then 29 needs a little work in that area before it is ready for prime time.

I hope this information will help, and I will check back and see if you see something different.

If this has to do with history, then it is a bug because any other browser can do this without a problem and so can FF 28.

If you see something else...I'll be watching with interest.

Kind Regards,


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Hello john99 and all--

I see I have made a tangled mess of these threads, though that was not my intention. I have tried the two suggestions you emphasized.

What it did was start up FF 29 Portable, made it temporarily my default browser. Ran my "check a bunch of email links" test. It would hang, as I expected on close. Then I disabled my plugins. This did not help. I ran it in Safe Mode but that did not help. Finally, I reset FF 29 to it's default state and that DID seem to work, but, truly, I cannot run 29 in its default state and not clear history, or accept everyone's cookies in a working environment. I do not believe I should have to. That's why we have these options, correct?

As above, I did do the two things mentioned and the results for disabling plugins and extensions did not help alone. Default State did seem to work, but repeating my self, I cannot use my browser in it's default state very usefully.

Next, I recopied everything removed back into my Portable FF 29 and ran the "check a bunch of email links" test, only this time I did not try to exit after each page opened but continued to open each page in a new tab. When I was done, I closed the tabs one by one and then exited. That worked, at least that time. I was watching in the Task Manager while doing this and I noticed a second, maybe, before FF 29 would exit the TM.

privacy.sanitize.sanitizeOnShutdown is set to True

Any further Ideas? I am going to surf around a little with 29 and see how things are.

Kind Regards,


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History Discussion

Well after reading that, all credit to Marco Bonardo Bugs are intended for development work but he has taken time to explain some misconceptions to those commenting in a bug, and explained the Mozila thinking on History. As you said he has also written an addon to do what some people desired & to correct a deliberate feature regression.

That is demonstrating the advantage of Firefox and this philsophy. If something is not essential or used by the majority do not leave it as something built in, use an addon instead.

Such conversation would also normally be off topic in this forum. Development issues and decision are only temporarily connsidered on topic here because of the Release of Firefox 29 & the need to have some background discussion and explanation.

History /Cookies & Restart problem

This is a bug as in fault. It is still not clear what is causing this. It may for instance only affect users with some particular addon or addons. It also seems to be occur only with some none standard preference settings. So that is probably part of the reason it is hard to reproduce and has so far gone unnoticed.

Constructive idea for troubleshooting temporarily use default prefs.
Would you mind trying to set your prefs temporarily to the default settings ? There is a good possibility the issue will then go away. No it is not intended as a cure. What I am hoping is that if Fx29 works ok with default settings we can quickly discover which one or two trigger the problem. That is both a potential workaround, and a clue as to what is the root of the problem.

Possible Steps To Reproduce
I have not tried this myself yet but have a look at this post /questions/997918#answer-567826

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Hello again John99--

Thank you for your feedback, and I'm sure you, like me, would like to not be answering endless emails, etc. I'll try to be brief.

1st, I am glad someone has introduced this as a bug...finally. But it looks as though he may not follow through... :-\

2nd, Development "issues" may be off-topic but the history issue is important to me and Mozilla Firefox's whole philosophy, beyond security and functionality, has been user customization. I did not need or want history taking up disk space that went on for over 6 months. I ended up with the choice of all or nothing and I chose nothing. But enough about that.

3rd) Options about History, Cookies, Exceptions are least to me. More Malware and Privacy issues abuses are introduced into a system through cookies than anything else, I believe. Sooo...

Last) I do mind setting my prefs to default. I don't want the huge history and I want to be able to pick and choose what cookies I will accept for the reasons above. As reported in previous post, default settings *did* seem to help, but I don't want the default settings.

I know you told me "..feel free to use a unsupported, vulnerable browser if you want to..." But a week ago it was a supported and secure browser (as such things go). I believe that this problem will be resolved by someone (hopefully). If not, I'll have to install 29 and teach my wife how to always check and kill the process in the Task Manager before she walks away from the computer...but it should not be this way.

Thanks again. I'll leave you alone for awhile unless you post back. I think all of us are more than a little burned out from this.

Kind Regards,


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Note that support for CAPS prefs like capability.policy.* has been removed in Firefox 29, so you can no longer do this via user.js
You can see that because they will show in Firefox 29 on the about:config page when they were previously hidden.

Did you try to exclude the cookies from clearing via "Clear history when Firefox closes" and let them expire when you close Firefox?

Modified by cor-el

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Chosen Solution

I now (temporarily) believe this bug or issue has its roots in the "Clearing of History on Exit" setting.

I took the plunge after some further playing around with the PortableFirefox 29 and reading the blog post linked here:


...and installed FF 29 over my previous FF28 on my box. I have unchecked the "Clear History on Exit" which was only deleting my history, not cookies or anything else, cor-el. My setting are not to accept cookies unless I make an exception. Until the FF developers find a way to make this functional, I will have to simply delete history manually.

By the way, John99, you would want privacy.sanitize.sanitizeOnShutdown set to "False", not "True" if you want to stop the automatic (attempt) at deletion of history on exit.

I have been running for about 6 hrs. without experiencing the "hanging" bug. So I can live with that for now until this bug is fixed. It should be fixed...browsers are supposed to be able to do things like that.

On the other hand, I might find things go bad...but so far I am not having a problem.

I have been running for several hours and will let you know later whether things change.

Kind Regards,


Modified by Axis

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Axis, Agreed. Safe Mode or Reset and lose everything to me is not an answer but a last resort.

I have been using FF since 1.0 and am reluctant to make jumps (stayed on 3.28 until an often used site changed, and I had to change) then since moving to FF12, would not make jumps until a version was 3-4 cycles old. The versions in my office have been more and more seeming to be slower compared to my home version.

A second profile worked for me and likely got rid of years of obsolete preferences and drag downs (I agree, the browser should be able to do this on its own, but some are likely from old add ons). With a second profile you can bring up the new version and work/tweak it to your liking at your own pace but you still have the first profile.

How I did it. I loaded FF29Beta, using custom install to change the directory to, "C:\Program Files\Mozilla Firefox29\". After loading, Do not open FF29. Next, create a second profile (just create the profile, nothing more (firefox.exe -profilemanager), by only adding the name for Enter New Profile (I used "29"). Then on the icon that was created when you loaded FF29, go to properties and enter in the startup command, "C:\Program Files\Mozilla Firefox29\firefox.exe" -P 29 [29 being the name you gave the profile] The double quote before the C:\ and after the .exe are necessary. (I also changed the startup command of my original firefox default version by using "C:\Program Files\Mozilla Firefox\firefox.exe" -P default -no-remote. When in the profile manager get the names of the other profiles which are generally the extension of the profile in your profile folder.

[[EDIT:I am so satisfied with the speed and lack of problems after doing a clean install, that I would suggest the clean install. Since this originally was posted I did the upgrade from FF26 to FF28, then to FF29 to see if there was a difference and had the myriad of problems mentioned, hangs when clear history, bookmarks backup, firefox already running, etc. I do not have those problems with the clean install version. So, in the past week I have determined to only use FF29 and have discontinued use of FF26 and FF28. Unfortunately, you might want to use the profiles until you get it up to speed as suggested in the balance of this post. And, if you do use a profile, do not use -no-remote for the browser you will use as default. I found that when I used it, any links, such as from Thunderbird, or other objects that should open in the browser caused a popup "Firefox is already running". Removing this -no-remote resolved the problem. As I see it, without the -no-remote it is treated as the default.]]

Back to reloading the programs. I then opened both FF26 and FF29 separately. From the FF26 version, I exported all the preferences I was able to copy from the add ons that have that capability. In FF29, I loaded those add ons new from the add on site, then imported the preferences.

I then loaded my other add ons that don't have the export/import feature. For those that store settings in the profile, (e.g. greasemonkey scripts, adblockplus), I just copied them over (but you have to open the greasemonkey scripts through the browser to get them to load). I also copied bookmarks as well as places.sqlite, signons-sqlite (paswords), permissions.sqlite, key3.db, and the chrome directory since I use userchrome.css and usercontent.css changes. This brought my history, passwords, etc. Do not copy extensions.* or prefs.js. I then started the browser and it was nearly the same after restart with a few more tweaks to the UI (User Interface) using Classic Theme Restorer add-on and userchrome.css and Stylish.

Looking at the directories you will see there are so many less files in FF29 than in FF26. It took all of about 2 hours. . . and a bit of 1 day to figure out the firefox is already running issue.

CAVEAT: I have to be frank, I do not believe my firefox already running issue is the same as others were having, but I do know that if I went with the upgrade, I would have the issue, but the clean install avoided it.

Modified by dmcff1

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Hello dmcff1--

Thanks for your reply. In my case it is completely and simply a case of needing to uncheck "clear history when Firefox closes." Then the hanging stops. You can read a bit about it if you wish here:

which deals with another issue as well and describes the whole "history" deal in more, uh...detail.

I can't really mark this as solved but if you read the link above and the response below you will find out that the developers did many "things" to FF in the move from 28 to 29. I think they are preparing us for "30."

Kind Regards,


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