edit fix found! You could downgrade, but it would be recommended that you downgrade to Firefox 3.6 as that is still supported, whereas Firefox 5 and 6 are not.

• see installing a previous version of firefox

Any problem is quite likely to be related to the plugins or add-ons that you use rather than to Firefox itself. Such problems are often quite specific to the setup and combinations of software extensions used, so if you do have a problem with Firefox not responding it may help to start your own thread with full details of your own setup.

If you are getting a message saying it is not responding then probably nothing is actually crashing.

If you do get a crash it could be (in order of severity)

• your OS: Windows that crashes,
• the Firefox Browser itself,
• or a Firefox process running as a plugin container.

Firefox itself is usually quite stable and responsive. (You appear to be using a 64 bit computer system, so problems are unlikely to relate to the machine not meeting Firefox minimum specs)

First of all try in firefox's safe mode but do not make changes when you get the check list just click on continue. If that fails to help, next try disabling or even uninstalling any plugins and themes. See troubleshooting plugins.

If all else fails fall back on the guide

• basic troubleshooting <-- blue clickable link --

Update
possible cause and workaround

I disabled all add-ons and it still happens intermittently, doesnt matter what I'm doing, watching a video or on a forum is freezes up says (firefox is not responding) the cursor turns into the blue timer circle thing and last about 30 seconds before everything comes back.

Did you also try disabling plugins. I have noticed a few reports of FlashPlayer causing problems or crashes on Firefox 6 it would certainly be worth specifically disabling that to see if it solve problems, and also ensuring Flash Player is uptodate.

It may be worth trying to check FlashPlayer is up to date using both

• the Mozilla plugin check
• and Adobe's own test page

Your system details seem to suggest you are up-to-date as it shows v 10.3r183 and Adobe's site is currently showing for all OS v10.3.183.7 (Unless the trailing 7 indicates a more recent security release or something).

Ok flash was 1 version out of date so I'll give it try.

The problem is even if I have my page sitting on google and I'm not using the laptop every 5-10 minutes the freezing thing happens for 30 secs, Ive been using chrome for the last 2 days as I work from home and this freezing thing is making using the net through firefox a chore, hopefully its the flash that was causing if it hasnt frozen in the next 2 hours I'll report back!

The freezing just happened again, only it was shorter this time only around 10 seconds, might be something to do with flash?

Nah went back to 30 seconds freezing now? what else could be causing it?

You could try disabling Flash when it is not needed. Although I have noted users on 64 bit systems reporting problems and saying they have with FlashPlayer the majority of users probably do have Flash Player installed, and the few that are reporting problems clearing up on re-installing flash may be coincidences.

It will be worth watching the forum, just incase a flurry of posts appears and someone finds the reason.

I did all the trouble shooting tips and it seems to be the themes causing my problems. I changed to my default theme and it is working fine right now with no freezing.

If it is the themes (which I love), should I get rid of the ones I have and re-install them, or just get rid of them completely?

Hmmm I dont have any themes/persona's dont like them I even tried a bare bones firefox with addons, plugins everything off still the same thing, is there any console within firefox so I could monitor what its doing at the time?

When it happens the CPU usage goes to 50% it doesn't effect my laptop I can still use it as normal, go to the desktop, open folders, look at pictures etc (which is what I do when I'm waiting on FF coming back) I'll keep an eye on the forums there are 3 threads reporting this issue I have click the "I have this problem too" in the 3 forums.

The total reports over the 3 forums is 826 people...

If you google "firefox 6.0.2 freezing" the top 3 results are the 3 threads I'm talking about, there's tons of replies we must all have something in common, some of the replies are saying they are running on a mac, I'm on windows... anyhoo I'm using Chrome for just now but I'll keep checking back on here.

Thanks.

To find out what is happening on a windows machine consider using sysinternals process explorer, it gives more detail than the Windows Task Manager. Firefox is likley to slow down if heavy paging occurs, or if CPU usage maxes out. If you are using a video stream, consider experimenting with hardware acceleration turned on and off, and remember streaming speed from the internet could become a limiting factor.

If you want to see where memory is being used try keying about:memory into the location bar, note the results have explanatory tooltips that are visible on mouse-over, and newer improved versions appear on the other Firefox channels.

Remember also to watch the process plugincontainer.exe not just firefox.exe

FireFox 3.0.6 with NoScript on Win7 Sp1 64-bit. I have done the basic troubleshooting. The problem persists with add-ons disabled. No themes here. After reinstalling, the problem persists. My system, HP Pavilion dv6-3155dx is quad core. When the problem occurs, I get the spinning blue circle for 30-60 seconds. Task Manager always reports firefox.exe CPU utilization of 25%. Affinity shows that all CPU cores are available to Firefox. plugincontainer.exe is reporting 0% CPU usage when this occurs. This occurs several times per hour. Antivirus is Trend Micro Platinum, no malware detected. I use Secunia PSI to ensure all related programs are up to date, and have a 100% score on PSI. I will try Sysinternals Process Explorer to see what additional info may provide a clue. Also the graphics adapter could be an issue; FireFox troubleshooting info suggests upgrading but HP seems not to offer a relevant upgrade.

Caught a SysInternals screen capture while it was happening.

I'm trying this as a workaround .... turn off crash reporting.

Still happening. Here's the stack info on the last recurrence: mozsqlite3.dll!sqlite3_bind_parameter_index+0x1f190 mozsqlite3.dll!sqlite3_step+0xd9 xul.dll!?CanUseOpaqueSurface@Layer@layers@mozilla@@QAEHXZ+0x1d81 xul.dll!?CanUseOpaqueSurface@Layer@layers@mozilla@@QAEHXZ+0x1c58 xul.dll!?CanUseOpaqueSurface@Layer@layers@mozilla@@QAEHXZ+0x1bc6 xul.dll!?FetchGlyphExtents@gfxTextRun@@QAEXPAVgfxContext@@@Z+0x18e2 xul.dll!NS_GetXPTCallStub_P+0xa94 xul.dll!?IsOriginalCharSkipped@gfxSkipCharsIterator@@QBEHPAH@Z+0x28f9a xul.dll!?GetEffectiveClipRect@Layer@layers@mozilla@@QAEPBUnsIntRect@@XZ+0x659 MOZCRT19.dll!_endthreadex+0x78 MOZCRT19.dll!_endthreadex+0x106 ntdll.dll!RtlInitializeExceptionChain+0x63 ntdll.dll!RtlInitializeExceptionChain+0x36

Assuming you have determined firefox is not crashing and you consider the system to be free of malware then, see if you can work out steps to reliably produce the freeze problem preferably with a couple of named sites, or some test file

• in safe mode
• with all plugins disabled
  (other than FlashPlayer, if problem is only with Flash Player sites)
• if possible even in a new clean profile
• with the current release
  (and if possible also the latest nightly - if problem does not exist in nightly it may be considered already solved and not suitable for developer attention)

You could then consider trying to post a bug about the problem at https://bugzilla.mozilla.org/.

Part of the difficulty of course is that with such a large userbase, a large proportion of whom will have FlashPlayer it is hard to know whether there is a correlation between the posts & votes, saying firefox freezes or whether it is just coincidence. (Contributors to a thread have the problem in the thread title, but that is not a random sample of firefox users; it is a very heavily biased selection)

You could even initially post your steps to reproduce in one of these threads, see if others can get the same results, it could aid your filing a bug; and then have a developer investigate it; if you could have others confirm it occurs in a precise set of circumstances.

(You have hundreds read these threads judging by the votes, but not many will read bugs, so making an initial post in the forum thread first, may make more sense than trying to post a bug prematurely.)

I haven't had a recurrence since creating a new profile. To everybody else experiencing the same problem, you might consider this step and see if the issue recurs for you.

I could find no "rhyme or reason" as to when this issue happened. However, on several recurrences, mozcrt19.dll seemed to be the culprit -- consistently consuming just below 25% of CPU, and that was consistent with prior task manager reports of 25% CPU usage by firefox.exe each and every time this hang occurred.

So ... new profile ... seems to do it, so far.

I have flashblock so in most sites visited there will be no flash going on (until I say otherwise), so it's not flash.

I have perceived the problem since a few days ago when the upgrade happened: Firefox just goes on rampage of resource usage and saturates CPU (System Monitor does not detect any other app but firefox-bin, which right now uses 6% but then may suddenly go up to 85%, whatever is needed to add up to 100%!)

It happens a lot when I browse my bookmarks and/or load a new tab. But also randomly.

If, using System Monitor, I command Firefox to stop and then continue, things go back to normal. However it is a bad workaround.

Do you have McAfee Site Advisor plug-in? Mozilla had disabled that plug-in with previous Firefox versions because of similar problems. I noticed after I upgraded to 6.0.2 that the plug-in was enabled, again, and I was having all kinds of memory, CPU usage, scripting error messages and Firefox and system responsiveness issues. I disabled the plug-in about 2 hours ago and all the problems went away almost immediately.

Try clearing browsing history. Or stop Firefox, remove places.sqlite, start Firefox.

For me, places.sqlite is in c:/Users/<bla>/AppData/Roaming/Mozilla/Firefox/profiles/<bla>/

I had a 83 MB places.sqlite. Getting a stack trace and checking modification times of files in the profile directory suggested places.sqlite was being updated at the time of a freeze (sqlite3_reset call in stack trace, as in another post here). I used to get one minute freezes a few times an hour, also in safe mode; after removing places.sqlite no freezes in a day.

Didn't Firefox get a new version of sqlite recently?

CARE

places.sqlite stores your current bookmarks and history. Firefox will try to recreate it but removing it unless it is known to be corrupt is not often recommended.

• see http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox

Changes are being made to how places.sqlite is used and the cache files it generates, that will be seen in Firefox 9 (Bug 674210)

Note also possibly the use of an add-on called cybersearch has been associated with places.sqlite problems (Bug 674475 ) {Please do not post in bugs unless you are a developer, started the bug, or have vital info such as a test case or regression range} Bugz Nettiquette

NB Clearing browser history may clear cookies, and a current known bug will then often creates multiple instances of plugincontainer.exe that could temporarily cause a slowdown or freeze of firefox.