I don't know whether your profile folder, having been updated to Firefox 4, still is compatible with Firefox 3.5. But you can try. Before uninstalling 4 and installing 3.5.18:

Make a backup of your computer for safekeeping. To back up Firefox, see Backing up your information.

The U.S. English installer for 3.5.18 for 32-bit Windows is here: http://ftp.mozilla.org/pub/mozilla.org//firefox/releases/3.5.18/win32/en-US/

If that's not the best version for you, navigate around on the server until you find what you need.

After installing, if your settings/extensions are too much of a mess, you could:

Create a new (blank) profile: Managing profiles.

Move key settings like bookmarks from your damaged profile to the new profile, see: Recovering important data from an old profile.

Hope this helps.

Rolling back to Firefox 3.5 is not recommended and you will have to create a new profile (or delete all sqlite files) because Firefox 3.5 uses an older version of SQLite that isn't compatible with the version used in Firefox 4. Rolling back to Firefox 3.6.x shouldn't be a problem.

Hi cor-el,

Rolling back to Firefox 3.6.x is not an option for me because every version of Firefox 3.6.x I've tried, including the final version, has the same "hanging/freezing/not responding" problem that Firefox 4.0 has. (Firefox 4.0 has other significant problems, but if the "hanging/freezing/not responding" problem is not resolved, and it has become apparent that Mozilla has no intention of trying to resolve it, then any other problems are moot to me.) It sounds like what you're telling me is that I'm essentially out of luck because there's no way I can go forward using any version of Firefox. I can't use Google Chrome because it's unable to import any of my Firefox 4.0 bookmarks and settings, even though it has a function do so; I can't use IE 9 because it is incompatible with Windows XP; and I can't use my IE 8 browser because it has its own unique and significant set of problems and because it's insecure.

Did you check your security software?

Make sure that you allow full access for each new Firefox version.
Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process.

You can 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"

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

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Hi cor-el,

Instead of changing my firewall settings to see if they were causing the "hanging/freezing/not responding" problem with my Firefox 4.0 browser, I went a little further. Following are two tests I tried.

For the first test, I changed my Firefox 4.0 home page to "New Tab" so that nothing on the internet would be accessed when the browser was started. Next, I shut down my firewall (COMODO) so that it was no longer running. Immediately after doing that, I disconnected my computer from the Internet. I then started Firefox 4.0 and let my computer idle. After idling for 5 minutes, Firefox 4.0 hung, pegging a constant 50% of the CPU. Before it hung, the CPU usage ranged from 0% to 2%. I tried to end Firefox 4.0 normally, but got the Microsoft unresponsive program window informing me that firefox.exe was not responding, at which point I used the "End Now" button to end it. Even though Firefox disappeared from the Task Bar, it was still running and still pegging a constant 50% of the CPU. I then killed the firefox.exe process via Microsoft Process Explorer (basically the same as Task Manager but with more features).

For the second test, I disabled my anti-virus software (Avira AntiVir Personal). With "New Tab" still my Firefox 4.0 home page, with my firewall still shut down, and with my computer still disconnected from the Internet, I started Firefox 4.0 and let my computer idle. After idling for 5 minutes, Firefox 4.0 hung again, pegging a constant 50% of the CPU. Before it hung, the CPU usage ranged from 0% to 2%. I tried to end Firefox 4.0 normally, but got the Microsoft unresponsive program window again informing me that firefox.exe was not responding, at which point I used the "End Now" button to end it. Even though Firefox disappeared from the Task Bar, it was still running and still pegging a constant 50% of the CPU. I then killed the firefox.exe process via Microsoft Process Explorer again.

Based on my two tests, the Firefox 4.0 "hanging/freezing/not responding" problem does not appear to be related to my firewall or my anti-virus software. I haven't tried creating a new profile yet to check if my current profile is causing the problem because I would first like an explanation as to why a problem with my current profile would trigger the "hanging/freezing/not responding" problem without fail after my computer has been idling for only 5 minutes. What is Firefox 4.0 trying to do after the 5 minutes of idle time? Why should it care that it has been idling for 5 minutes? Is it keeping track how long it's been idling?

I've been using Firefox for over four years, and I did not have the "hanging/freezing/not responding" problem with any version of Firefox prior to the first release of Firefox 3.6.x. After using that release for a couple of hours, during which time I kept encountering the "hanging/freezing/not responding" problem and other severe problems, I uninstalled it and reinstalled the latest release of Firefox 3.5.x. Thereafter, I would occasionally install the latest release of Firefox 3.6.x to see if the "hanging/freezing/not responding" problem had been fixed, but it never was, so I always had to uninstall it and reinstall the latest release of Firefox 3.5.x. I never had a problem going back to any release of Firefox 3.5.x. Whatever is causing the "hanging/freezing/not responding" problem, it began with the very first release of Firefox 3.6.x and has continued through Firefox 4.0, and many Firefox users have experienced the exact same problem as I have.

Well, it looks like Mozilla is going to ignore the "hanging/freezing/not responding" problem with Firefox 4.0, just like they did with all versions of Firefox 3.6.x. Between the "hanging/freezing/not responding" problem, crashing, "script stopped running" errors, Web pages not being restored correctly for the tabs that are restored when restoring a previous session, missing the New Tab Button on the right side of the last tab, toolbar customizing that doesn't work as advertised or at all, an awesomely slow Awesome Bar that doesn't work as advertised or at all (even when it displays something, it is totally unrelated to the Web site I want to visit, and the display occurs after I've fully typed in the address of the Web site I want to visit, and I am not a fast typist), add-on displays in the Add-on Bar randomly swapping positions and not being able to put them back where I want them, not being able to put separator lines between add-on displays in the Add-on Bar, slow start-up, and taking at least five minutes to close, I can't find anything to recommend Firefox 4.0. Hopefully, some or all of these problems will be resolved with the release of Firefox 5 on the scheduled release date of June 21, but based on past history, most notably the "hanging/freezing/not responding" problem with Firefox 3.6.x that wasn't fixed with Firefox 4.0, I doubt that any of the aforementioned problems will be fixed with Firefox 5. Google Chrome is unable to import my Firefox 4.0 bookmarks; otherwise, I would switch to it. And IE 9 is not compatible with Windows XP, which is my operating system, and IE 8 is insecure, so I am left without a good alternative to Firefox. If I could roll back to Firefox 3.5.18, I would, but that is not feasible.

The "hanging/freezing/not responding" problem is driving me crazy, so I have to do something. Does anyone have any recommendations?

I'm finding more problems with Firefox 4.0, but all the problems I've found with it pale in comparison to the "hanging/freezing/not responding" problem. It's bad enough that Web pages often don't render properly in Firefox 4.0 -- I know this because of the way they used to render in Firefox 3.5.18 and the way they currently render in IE -- and that it crashes sporadically, especially when I close it. Even if Web pages render properly the first time around, they render slowly -- just as slow, if not slower, than Firefox 3.5.18 -- and they regularly don't render properly when I do a session restore. Some Web pages are unable to render properly at all in Firefox 4.0. Compare how scrolling looks for Google Images pages in Firefox 4.0 versus IE. Scrolling Google Images pages in Firefox 4.0 doesn't work cleanly like it does in IE. And why is it that when I change my Google preferences, the Google Preferences page ALWAYS works differently -- definitely not better -- in Firefox 4.0 than it does in IE and the way it did in Firefox 3.5.18? I'm also still getting a lot of scripting errors in Firefox 4.0. All in all, Firefox 4.0 is a mess. Maybe that's why Mozilla is coming out with Firefox 5 so quickly, but I doubt that the "hanging/freezing/not responding" problem and the Web page rendering problems, as well as other problems, will be fixed with the new release.

Have you tried a new profile yet?

To move your bookmarks to Chrome, one of these might work for you: (1) export your Firefox bookmarks to an HTML format file (Chrome may be able to import that); (2) import the HTML format file into IE Favorites first, and then Chrome may be able to pick them up from there.

I haven't tried creating a new profile yet because I'm not convinced that my profile is the cause of the "hanging/freezing/not responding" problem. I'm assuming that the suggestion to create a new profile implies that my places.sqlite file may be corrupted. If it is corrupted, how would I know, how would that explain the 5 minute idle limit, and how would that explain why the "hanging/freezing/not responding" problem only occurs with Firefox 3.6.x and 4.0 but not with any version of Firefox prior to 3.6.x? Every time I would upgrade to the latest version of Firefox 3.6.x, which I couldn't tolerate keeping installed for more than a couple of hours, from the latest version of Firefox 3.5.x, the "hanging/freezing/not responding" problem would occur without fail, but when I would restore back to the latest version of Firefox 3.5.x, the "hanging/freezing/not responding" problem would cease. Why? If my places.sqlite file is not corrupted, then the problem lies elsewhere. If my places.sqlite file is truly corrupted, and there is absolutely no indication that it is, it would be impossible for me to recreate it from scratch. I'm confident that if I create a new profile with a new (i.e., unpopulated) places.sqlite file, I would no longer get the "hanging/freezing/not responding" problem, but how would that help me? Unless it can be proven that my places.sqlite file is corrupted -- if it is and it can't be fixed, then I'm really screwed -- or that my Firefox profile is the cause of the "hanging/freezing/not responding" problem, I'm not going to touch my existing profile or create a new one. In the meantime, I'll work on trying to import my Firefox bookmarks into Google Chrome. If I succeed in doing that and find that Google Chrome meets my needs and works fine, I'll get rid of my Firefox browser. It's a shame that Mozilla seems to have no interest in resolving the "hanging/freezing/not responding" problem. Hopefully, someone from Mozilla can let me know someday if or when this problem is fixed.

This is a mispost. Apparently, there's no way to delete it.

Mozilla takes crash reports very seriously, and if you've had a crash, you know about the reporting system that pops up. But hangs and freezes don't generate crash reports, so we have to go through a set of diagnostic steps to try to determine whether it is Firefox, an add-on, a preference setting, particular web sites, or the system on which Firefox is running.

I appreciate that your scientific instincts lead you to ask exactly what is causing the problem. Creating a new profile for testing purposes is one way to rule out problems with add-ons and settings -- and the files in your profile folder such as sqlite databases. You can run the new profile for a while, then import your bookmarks. Okay so far? Try your main add-ons. Okay so far? Try your favorite settings tweaks, if you have resisted doing that for this long. Any change? Et cetera.

A new profile can be a laboratory for experimentation, it need not be a concession of defeat. And what you learn and report here contributes to the Mozilla community, whether you discover a bug in Firefox, or an unfortunate interaction between add-ons, or a previously unnoticed security exploit.

You've put a lot of thought and energy into this thread, and I hope you can take a little more time to try the new profile experiment for a day or two.

As soon as I have a sufficient block of time, I will try the new profile experiment, which I will need to do within one day. My approach thus far has been from my background as an applications programmer for over 30 years. As much as I would like to avoid having to become involved in trying to debug third party software, I will draw on my background to do so with the new profile experiment. The experiment will be time consuming, and I don't want to waste too much of my time on this, so if I see it's taking too long or I wind up back where I started (i.e., that my places.sqlite file is somehow causing the "hanging/freezing/not responding" problem), I will turn my attention to trying to import my Firefox bookmarks into Google Chrome. In the meantime, I can't understand why anyone affiliated with Mozilla doesn't have a clue as to the significance of the 5 minute idle time limit that causes Firefox 4.0 (and all versions of Firefox 3.6.x) to "hang/freeze/not respond." It's a shame that I will apparently be the only person who will ever have worked on this problem.

I've decided not to waste my time trying to debug the Firefox 4.0 "hanging/freezing/not responding" problem for the following two reasons:

1) I have since encountered more problems so profound as to qualify Firefox 4.0 as a genuine mess. I don't believe it is worthwhile to document all the problems I encountered because of reason #2 below. I will say that one of the problems has prevented me from bidding on, and potentially winning, items on eBay, making me very angry.

2) Mozilla has just released Firefox 5.0.

I'm going to wait a little while before installing Firefox 5.0. When I do install it, if I discover that it has the exact same problems as Firefox 4.0, I will replace it with some other browser. The problems I have encountered thus far are intolerable and unacceptable. Mozilla must have known Firefox 4.0 was a disaster considering how quickly they released Firefox 5.0. If there was any possible way to roll back Firefox 4.0 to Firefox 3.5.18, I would, but I would still be looking to replace Firefox with another browser.

You can try Process Monitor to see what is going one after you leave Firefox idle.

• http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx Process Monitor

You can also try to boot Windows in Safe mode (F8 on boot screen) to see if that helps to identify the problem.

I am sorry that MusicFan is dropping out of this thread -- I encounter this problem with Firefox 7.01 on Windows 7. I don't see the "places.sqlite.corrupt" file, though.

This is one annoying, frustrating problem, and I have resorted to using Chrome when I need to get work done (eMail, for example)...

I have noted that Resource Monitor correctly identifies Firefox as "not responding", but I am not sure where else to look for any other hints as to cause & effect... Perhaps someone can suggest if any of these extensions could be causing the problem:

Application: Firefox 7.0.1 (20110928134238) Operating System: WINNT (x86-msvc)

- Adblock Plus 1.3.10

- Add to Amazon Wish List Button 1.7

- BetterPrivacy 1.67

- Boomerang for GMail 1.0

- Extension List Dumper 1.15.2

- Freecorder Community Toolbar 3.7.0.6

- HTTPS-Everywhere 1.0.3

- Logitech Device Detection 1.23.0.5

- McAfee SiteAdvisor 3.4.0

- Media Converter 1.0.3

- NoScript 2.1.4

- Password Exporter 1.2.1

- Springpad Extension 2.3.1106.29.2

- Tab Control 0.5.5

- TooManyTabs 1.3.7

- WOT 20110704

-- OR -- these plugins:

Application: Firefox 7.0.1 (20110928134238) Operating System: WINNT (x86-msvc)

- Adobe Acrobat 10.1.1.33

- Google Earth Plugin 1.0.0.1

- Google Talk Plugin 2.3.2.0

- Google Talk Plugin Video Accelerator 0.1.44.11

- Google Update 1.3.21.69

- Google Updater 2.4.2432.1652

- iTunes Application Detector 1.0.1.1

- Java Deployment Toolkit 6.0.260.3 6.0.260.3

- Java(TM) Platform SE 6 U26 6.0.260.3

- Logitech Device Detection 1.23.0.5

- McAfee SiteAdvisor 3.4.0.135

- Microsoft Office 2010 14.0.4761.1000

- Microsoft Office 2010 14.0.4730.1010

- Picasa 3.0.0.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- QuickTime Plug-in 7.6.9 7.6.9.0

- Shockwave Flash 10.3.183.10

- Silverlight Plug-In 4.0.60831.0

- Windows Live™ Photo Gallery 15.4.3538.513

The reasons I let this thread slide are given in my last entry and because I was never provided an explanation as to why Mozilla couldn't figure out why the "hanging/freezing/not responding" problem did not exist in any form in any release of Firefox prior to the first release of Firefox 3.6.x.

The "hanging/freezing/not responding" problem has persisted through all releases of Firefox 5.0.x and 6.0.x, and I was going to resurrect this thread as a new thread in reference to Firefox 6.0.x, but Firefox 7.0.x came out too fast.

With the release of Firefox 7.0.x, Mozilla has fixed the problem where Firefox hangs after being left idle for 5 minutes. Now I can go to the bathroom, take a phone call, or do any other minor activity that lasts for more than 5 minutes without having to end Firefox. In other words, I can now leave Firefox unattended and idle for more than 5 minutes and not have to worry about it hanging. I can now watch videos that run for more than 5 minutes and not have to worry about Firefox hanging. This is a big step forward, but it is not the end of the "hanging/freezing/not responding" problem.

The "hanging/freezing/not responding" problem still persists insofar as it occurs constantly during all of my Firefox sessions while I am actively using it. Sometimes I get locked out of Firefox for more than 5 minutes before it finally responds, but the usual lockout time is between 1 to 2 minutes. It seems to occur most commonly when I open a bunch of tabs or bookmark a new link, but sometimes it occurs for no apparent reason at all. The problem is cumulative; the more tabs I open and the more links I bookmark during a Firefox session, the more frequently the "hanging/freezing/not responding" problem occurs, the longer it lasts, and the slower Firefox gets. I spend a lot of time waiting for Firefox to respond.

But the "hanging/freezing/not responding" problem is not limited to just temporary non-responsive episodes. On some occasions, I have to cancel Firefox when it has become apparent that it is inextricably hung. I have found that there are links from a particular Publishers Clearing House e-mail that cause Firefox to inextricably hang every time I use those links, causing me to have to cancel Firefox. I cannot discern a pattern for the other inextricable hangs, but idle time is not a factor. So, the "hanging/freezing/not responding" problem is still as exasperating as ever in Firefox 7.0.x.

It is my belief that the "hanging/freezing/not responding" problem is related to the size of the places.sqlite file. I could easily prove this by creating a new Firefox profile with an empty or sparsely populated places.sqlite file and with the same Firefox extensions I currently use, but I don't really have the time, and I am confident that there would be no "hanging/freezing/not responding" problem with the new profile. I use minimal and fairly standard extensions, so I don't believe they are a factor causing the problem.

I still think Firefox is the best available browser and will continue to use it as long as it does not become too much trouble to use. I'm hoping that Mozilla will fix the remaining "hanging/freezing/not responding" problems.