john99, thanks for helping me try to unravel this ever-more-perplexing mystery!

You mentioned in your first post that you hadn't read most of this thread--I don't blame you, War and Peace would be a briefer task! But you may not have noticed that I provided links to all six of the crash reports that I filed since this nightmare began, the first in my post on 1/21/2014 at 8:37 PM, the last five in my post at 10:33 PM on 1/26/2014. While the contents of these crash reports tell ME nothing, I thought that the expert eye can glean volumes from the merest glance. Is that another myth that needs shattering?

But seriously, I'm genuinely puzzled why we must still be conjecturing about all this if the answer lies in the crash reports--at every single opportunity that Firefox said it had crashed and presented a crash report, I sent it as requested. Do these six reports tell the expert nothing?

You mentioned Javascript, john99. Just for the record, despite considerable trepidation, I followed cor-el's instructions and went to about:config and changed two boolean trues to falses. (If nothing else, this whole experience has been instructive--until now my only encounter with boolean algebra had been a brief one in a math course I once took--if I'd known one day a boolean "true" could perhaps rise up and strike down my browser, I'd have paid more attention!!)

Oh, one last thing john99--I'm not sure why you mentioned "Flash" hangs and crashes. My hangs and crashes have NOT been triggered by Flashplayer, it's just that one of the many early manifestations of unresponsiveness is the absence of the video in YouTube. Eventually, the unresponsiveness becomes complete, and I can't even close Firefox by X-ing it out, I have to use the Task Manager (that is, if Windows doesn't appear in a box, telling me Firefox is unresponsive and I should close the program by clicking "close program" in the Windows box--when Firefox is unresponsive, sometimes this box appears, sometimes it doesn't).

Note, john99, all the while, Chrome has been performing flawlessly, so this is a browser-specific problem.

I am sure an expert could glean volumes from the merest glance, but I can not. The last lot of crashes were JS related. The mention of Flash Crash and hangs was because.

• They are very common, and often users do have multiple instances of Flash processes.
• You have Flash and other video related plugins
• Real Player & Flash software sometimes conflicts and has been known to cause Firefox crashes.

Not all Crash reports are even processed, if they are they generate the Crash Signatures. Anyone looking for patterns and solutions is interested in the Signature. Inevitably only the most common ones tend to get fixed. Filing a bug is the first stage in trying to get a fix. To simplify Crash Reports and bug fixing normally Safe Mode would be tried with no plugins, or only the one or two plugins needed to demonstrate the problem.

I do not wish to put you off submitting Crash Reports the data is needed. I would also suggest that you turn on Telemetry, again mainly to help others and developers

• Share data with Mozilla to help improve Firefox

To john99 and cor-el:

john99, thank you for your posts shedding light on all this--even the barest ray is blindingly brilliant to me, someone completely ignorant of the inner workings of Firefox.

It's interesting that you say that the crash reports indicate that "the last lot of crashes were JS related", corroborating cor-el's analysis of the first crash report. After following cor-el's instructions and converting some Boolean trues to falses last night, today I had several of what I'll call "classic" episodes of Firefox unresponsiveness, where Windows appeared and told me to click on "close program". As a consequence, I concluded that at least the alterations I'd made to config were unsuccessful, and so I changed them back to trues.

cor-el, john99, both of you have mentioned that investigating Add-ons is worthwhile. Rather than try to use Firefox in safe mode (again), because it really is difficult to accomplish anything with so many things disabled, I went through all my Extensions, Plug-ins, etc. and disabled every single one that is not truly important to me; it totaled quite a few, including every one of the very numerous RealDownloader-related ones. I'm hoping that the varmint responsible for all this mischief is among the many Add-ons I disabled. So far I've gone about two hours without a problem--if I get through tonight and tomorrow, I think we can declare victory. Keep all available appendages crossed, you guys!

Again, thank you john99, thank you cor-el, for your assistance. It's a very small band of top contributors who are essential to the functioning of Firefox, and I fear that we who receive your help often don't properly express our appreciation.

If you are having problems with relating to Real Player you could try using FlashPlayer with protected mode disabled. That is pretty easy to change if you are able to find and edit files.

• http://kb.mozillazine.org/Flash#Disabling_Protected_Mode_in_Flash_11.3
  I have no reason to expect that procedure to have changed in the current version of FlashPlayer

Presumably you have already updated FlashPlayer and are using version 12

However I would first of all try using Flash Player without RealPlayer related software enabled, and without protected mode enabled. Only after you are sure things are more stable try using RealPlayer again.

You may also find it convenient to use multiple Firefox profiles. You could have different profiles for certain types of work or tasks and easily switch between profiles, or even run multiple instances of Firefox.

Have a look at this thread for my suggestions to someone else

• https://support.mozilla.org/en-US/questions/981674#answer-522218

I just thought I would provide some interesting new information that may help in solving my severe problems with Firefox, problems which have relentlessly continued in the four days since my last post. To sum up my Firefox problems in a phrase, about five times a day Firefox either crashes, or becomes completely unresponsive and must be closed. Despite my disabling many suspect programs and making changes to JS, the problems have continued unabated.

But here's the new piece of information, something I first noticed a couple of days ago and have now confirmed and reconfirmed on multiple occasions.

First, I should say that I have had the Task Manager open in the task bar for quite a few days now because I wanted it instantly accessible to close Firefox when it became so unresponsive that I couldn't click on X to close it. And so I was in a position to notice the following very interesting phenomenon. But first, I must report that when Firefox is operating normally, even when I have many tabs open on different websites, some of which are running videos, and even when I have multiple Firefoxes open, the % of the CPU being utilized by Firefox is low, usually under 3 or 4 %, and often under 1 %.

But when it's in the first stages of becoming unresponsive, the CPU % being used by Firefox is over 25 %!! And here's what's even more remarkable: EVEN WHEN I CLOSE ALL TABS AND LEAVE ONLY ONE TAB OPEN AND IT'S A "NEW TAB", not at a website, the CPU % REMAINS OVER 25 %!!

Then, when I close Firefox and restart it, the CPU is back at it's usual level, less than 3% with multiple websites being visited in tabs.

So, clearly, Firefox's unresponsiveness in my computer is perfectly correlated with a massive, unprecedented increase in CPU use, an increase not caused by any unusual demands placed on it by me. But the question is: what is causing this abnormal CPU usage?

Incidentally, I have run repeated scans using Windows Defender and MalwareBytes and nothing malicious has been detected, and I have had no other problems with my computer besides the ones with Firefox.

Actually, I believe that 25% is quite normal on many computers. However, in your case perhaps not.

Madness has descended upon the world. Or, upon Firefox. Or maybe just upon my particular copy of Firefox. At this point, I've lost all perspective, and can say nothing with even the most modest sense of assurance and certainty.

Before I recount the latest twists and turns, please note (for those trying to make sense of this post): This thread was briefly continued in the thread "It will break my heart, but must I abandon Firefox?"---see

https://support.mozilla.org/en-US/questions/985122?

Please read that thread if you wish to fully understand the details of the recent, truly bizarre developments in this case.

This is to john99 and cor-el, and anyone else who feels they can contribute.

My last post was on Feb. 1, 2014 in the other thread. At that time I described the shocking discovery I had made. In the four days since then, I have closely observed the situation, and am able to confirm the accuracy of my Feb. 1 report, and can now add some details.

The salient, transcendent fact (before which all other facts are reduced to largely irrelevant trivialities) is this: When I turn my computer on in the morning, and open Firefox, Firefox uses less than 2% of the CPU and functions perfectly. This is true regardless of how many websites, and how many tabs I open, and keep open simultaneously, or how busy those tabs are. First thing in the morning, NO BURDEN is too great for Firefox to handle without mussing a hair on its head, i.e. without its straying beyond about 2% of the CPU's capacity.

But then, as the day progresses, even if I depart from all websites and close all tabs except for one "new tab" (just to keep Firefox open) the % of the CPU consumed by Firefox will creep up, gradually, insidiously. In fact, never has the word "insidiously" been more appropriate, because you need the mental equivalent of "time lapse photography" to recognize what's going on. And then, by the afternoon, when the Firefox % of the CPU exceeds around 25% (even with only a "new tab" open and, therefore, nothing going on in Firefox) Firefox will start to become unresponsive. First I will be unable to download files, then I won't be able to watch videos, then I won't be able to open new tabs, then I won't be able to change tabs--until, finally, I can do nothing at all, including close Firefox, and so I must resort to the Task Manager to do it.

Here's a very crucial point. If at any time during this inexorable process (of the Firefox CPU % rising) I close Firefox and immediately reopen it (in fact reopen it to the same array of websites I was on before closing it), the CPU % will drop back to its first-thing-in-the-morning low of less than 2%. If it was at 10%--back to 2%, if it was at 20%--back to 2%, if it was at 26% and becoming unresponsive--back to 2%, if it was at 29% and totally unresponsive--back to 2% and totally back to normal functioning!! Immediately!! Instantaneously!!

Let me quickly relate the various steps I have taken to eliminate confounding variables as you experts try to figure out what's going on. I already had made the recommended changes (advised by cor-el) in JS, I had disabled various add-ons--all for naught. In the past few days I went through every extension, plug-in, etc. and disabled every non-essential one, including every RealDownloader-associated plug-in, all the Google video talk plug-ins, and many others--this too, was all for naught. Then I took a very interesting step, on my own initiative--I sought, and found, a Firefox add-on that puts Adobe Flash Player in a disabled state unless you click on a button (where you'd normally see a video). I never realized how many advertising videos run (usually) silently on a website until I saw five or six of these buttons on many web pages. Anyway, I basically never allowed Adobe Flash Player to be active in Firefox during these past four days (just a couple of times so I could see how well the disabling add-on worked), and so (to answer a question posed to me by cor-el I believe it was) the plugin container for Adobe Flash Player for Firefox was no longer active, in fact it even stopped appearing in the Task Manager list of Background Processes. So, although Adobe Flash Player is guilty of much inadvertent mischief, for once it can be clearly shown not to be the culprit. Yesterday, for example, when the pattern described above played out and Firefox became unresponsive, I hadn't run Adobe Flash Player at all on Firefox.

Now, it's true that I have learned to cope with this unresponsiveness problem--when I see the Firefox CPU % has gotten to, say, 15% I can just quickly close Firefox and reopen it to the same array of tabs, it'll be back to less than 2% of the CPU and I'm fine for hours. So yes, I can live with this flaw if I have to, but do I have to?

No that is abnormal behavior, so I hope we can at least narrow down the cause.

I wonder if memory use is also increasing and even wonder about the state of the hard disk. Presumably all the CPU rising CPU use is firefox.exe

I have not the spare time available to look at this right now, and have not yet even reread this thread.

I have some ideas but only troubleshooting steps not solutions so I will wait to see if cor-el has suggestions.

Does running Windows in Safe mode has any effect?

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test.

TL:DR _{( 'edit comment by John99)}

The problem was apparently McAfee SiteAdvisor.
Disabling Site Advisor solves the issue in this instance.

To John99 and cor-el:

Well, guys, I think a solution may very well have been obtained.

Since my last post I was busy putting my new tool to work,i.e. the fact that an abnormal rise in the Firefox CPU % was a clear, quick, early indicator of trouble brewing, trouble that would only culminate in fatal unresponsiveness many hours later, when it climbed above 25%.

One bit of history: I think this all began around Jan. 19, and following the suggestion of you experts, early on in the trouble-shooting process I opened Firefox in Safe Mode--but a) because I felt crippled without so many necessary components, and b) because it took so many hours for the unresponsiveness to develop, and c) because I found out that Safe Mode didn't disable plug-ins, and I believed (mistakenly as it turned out) the most likely culprit was one of the plug-ins--because of all that I stopped the Firefox Safe Mode trouble-shooting method prematurely, unwilling to spend so much time in the hobbling Safe Mode given how unlikely it seemed that an extension was responsible, feeling instead that I should focus elsewhere.

However, once I had this invaluable tool of the Firefox CPU %, I knew I could very quickly definitively determine whether or not one of the extensions was responsible. So I opened Firefox in Safe Mode, and spent half a day in that mode, and watched the Firefox CPU % remain very low, with not the slightest tendency to rise during that period. So I felt a strong sense that we had clearly determined that in fact one of the extensions was responsible. So I restarted Firefox in normal mode and disabled three of the six extensions I was currently using, and allowed the three least likely culprits to operate. Again I observed for half a day, and again saw the Firefox CPU % remain very low-- basically under 2 %.

Then, yesterday, I enabled two of the remaining three disabled extensions, and observed for the entire day. Again, the Firefox CPU % remained very low, under 2%, exculpating those two.

While the process of elimination would seemingly irrefutably implicate the one remaining disabled extension, I felt that, as a baby cor-el or John99, I needed to provide the conclusive proof only a re-enabling of the remaining extension (and a subsequent reappearance of a rapidly rising Firefox CPU %) could furnish.

And so, today I re-enabled the last extension, and voila! After just a few hours the Firefox CPU % had risen past 2 %, past 5 %, past 10 %, past 15 %!! Should I have waited for it to surpass 25% and result in unresponsiveness? Perhaps, but at that point I felt even Louis Pasteur would have felt I had satisfied all the requirements of a rigorous scientific experiment, and I disabled that extension. Of course, the Firefox CPU % immediately dropped to its customary level, around 1 %.

And what was the culprit?: McAfee SiteAdvisor, a free piece of software that provides me with some additional security beyond Windows Defender and MalwareBytes scans. I've used it on this computer for about a year, and never had an unresponsiveness problem because of it--I have no idea why the difficulty should have suddenly arisen.

Anyway, we've had a happy ending, and I want to thank both of you guys, cor-el and John99, for your involvement and your help in solving the mystery! To me, the most interesting and, honestly, heart-warming thing about the internet is the way people will spontaneously, without coercion, decide to use their expertise to help those like me, someone beset by an intractable problem with almost no knowledge of the intimate details of the software experiencing the problem or the proper trouble-shooting process. So a hearty THANK YOU! John99 and THANK YOU! cor-el.

Good to know the problem is finally solved.

Glad you were able to stick with this and sorting out the problem.

We are aware that safe mode is inconvenient, even more so when we also suggest disabling all l plugins. It is often however the fastest method of getting to the bottom of a problem. Likely culprits may then be tested or lists bisected.

Solutions are easiest when we can see an obvious cause.
If we have to resort to troubleshooting we often need a base line and Steps To Reproduce. We can then say in configuration A) there is no problem but in configuration B) there is a problem what is different, let's try C)

As you mention your own issue is particularly dificult because the problem develops slowly.

A slightly different matter
I am not sure if HelpDesk may be interested in

• Trying to reach out to other users of McAfee site advisor to see if this is a common problem.
  http://www.siteadvisor.com/
• Try free McAfee site advisor themselves to see if the problem is easily replicated if so we may file a bug &/or include in our kb
• I have started a thread about this problem
  Is McAfee site advisor commonly causing Firefox problems? /forums/support-forum-contributors/709985

It may also be noted that the usefulness of McAfee site advisor may be rather speculative, given that Firefox by default already provides some similar protection

• How does built-in Phishing and Malware Protection work?

Mozilla's Blocklist shows a McAfee Site Advisor entry from last year dated March 8, 2012 (see bug 729614). The problem has happened before, with earlier versions of the add-on.

To AliceWyman: Given the information you have ferreted out about problems in Firefox due to some previous versions of McAfee Site Advisor, let me tie up what is now a bit of a loose end--I definitely haven't been using the old versions cited in your linked article, or, for that matter, ANY old version!! I let McAfee Site Advisor automatically update itself, and so I've always had the current version. I noticed they updated me on Feb. 7, 2014, so that means I've had the Firefox unresponsiveness problem due to McAfee through at least two different versions of the Site Advisor (I don't know if they've updated it more than once since the onset of my problems around Jan. 19th, though I doubt it).

John99, if you have the time, could you satisfy my curiosity? I'm just wondering if the "tool" that proved indispensable in my diagnosing the cause of my slowly developing unresponsiveness problem (i.e. an abnormal rise in the Firefox CPU %), could be utilized by others with unresponsiveness problems or crashes--in other words, do you have reason to suspect that a significant percentage of those problems are caused by (or simply correlated with) excessive Firefox CPU consumption, and the culprit could be pinpointed (and red herrings eliminated) more quickly by scrutinizing Firefox CPU % the way I did (after establishing a reference level that represents the normal Firefox CPU % in a particular computer)? I was able to rule things out (and, eventually, in) much more quickly than I could have done without monitoring the Firefox CPU %.

I do not know what you used.

I would imagine the usual tools for Windows would be from Sysinternals. There is also a very specific Firefox tool that could be of use the profiler.

• https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler

All are things that could be usefully documented and used by techies, but the average user probably struggles well before trying to get to that level of complexity. We do not even document multiple profiles and the profile manager. Things may change in the future but any new documentation has maintenance costs and is not worth it unless it is used frequently.

Some Firefox KB articles can exceed a million hits per month

• https://support.mozilla.org/en-US/contributors

John99, I was using the term "tool" figuratively. All I did was observe the Firefox CPU % (i.e. what percentage of my CPU capacity Firefox was using) in the Task Manager "Processes". Everyone has the ability to monitor that, and my question was, would such monitoring help to quickly identify the source of unresponsiveness or crashes in other cases. I have no idea if my situation is rare, very common or somewhere in between. By "my situation" I mean where the unresponsiveness and crashes were clearly correlated with a markedly elevated Firefox CPU %, and where I was able to swiftly rule out various add-ons, and eventually identify the culprit with certainty many hours before it caused another crash or episode of unresponsiveness--in other words I didn't have to endure many hours testing various add-ons, waiting to see if Firefox would crash or become unresponsive, I could tell in a short time based on whether or not there was a rising trend in the Firefox CPU %.

graviton37, I only linked to the Mozilla Blocklist entry dated March 8, 2012 at https://addons.mozilla.org/firefox/blocked/i72 to show that an issue with McAfee SiteAdvisor had occurred last year before. Quote: Versions of the McAfee Site Advisor extension older than 3.4.1.195 have a major memory leak problem that can make Firefox consume large amounts of memory and possibly crash after extensive use. All users should upgrade their McAfee software to the latest available version, which fixes the memory leak and isn't affected by this block.

I can see from the details of your original post that you had McAfee SiteAdvisor 3.6.5 but similar problems could redevelop in current or future versions of McAfee's product. You might want to visit McAfee Support or the SiteAdvisor forum, https://community.mcafee.com/community/home/web_email/siteadvisor to see if others are also having issues, assuming you want to continue using SiteAdvisor with Firefox.

graviton37,
Yes making use of the Task Manager (or whatever in other Operating Systems) is a good idea. I expect that is how most Firefox users become aware it is using high amounts of CPU.

Some become aware due to security suite utilities reporting high usage, but that may sometimes be rather premature. Any such warning may not always be reasonable. If for instance it reports the process with the highest CPU reading that may quite legitimately be Firefox when in heavy active use.

I have the same things happening with my usage of the latest version of Firefox version 30, from 25 up to 30, i have been getting machine dumps for netio.sys and sometimes ndis.sys while using the firefox browser. i have tolerated it enough til it occurs at the most inopertune time. I do not use mcaffe software, i throw it in the trash whenever i see it wanting to be loaded onto my machine. what is really frustrating it the BSOD what a pain. IS there anyone else out here that is experiencing the same thing while using Firefox?

ekunzler,

Please stay with your original question thread here: https://support.mozilla.org/en-US/questions/1006274

locking this thread