Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes). See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems

If it does work in Safe-mode then disable all your extensions and then try to find which is causing it by enabling one at a time until the problem reappears. You can use "Disable all add-ons" on the Safe mode start window to disable all extensions. You have to close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

you rock dude thank god this worked I was getting to the point of yelling at my computer because of the pop ups were getting worse! you rock thanks for helping me! :^D

So...what were the offending add-ons?

This really does work. I select Disable all add0ons, then I will start enabling one by one until I find the issue. I will try to remember to add a comment once I find it!

It was some older add-ons that caused this problem. Once you select disable add-ons, you will see which are not supported by 4.0 Beta 2. Just remove and restart. Then enable each one one at time and restart.

Hope this helps!

I got it to go away by (as someone already said) disabling all the add-ons and then enabling them one by one. The ones that were the problems were called 'Context Management Controller 2.8.0.4360' and 'Textual Media Service 2.8.0.4580'. I hope this helps.

This fixed my issue, disabled all add-ons. Turned out to be the telephony toolbar that our new voip system installed.

I found that the culprit for me was Zonealarm. FF Works like a charm with this disabled.

Michael Nunneley Post Falls ID

I found that the culprit was eSnips downloader toolbar.

GuardedID Toolbar 3.0 (Provided by Trend Micro) is the problem for my error of this type.

I have the same problem. I disabled all the Add-Ons and restarted Firefox, but the problem doesn't go away. I even reinstalled Firefox 4 and applied the newest java. Still no luck.

Have also got TypeError: Components.classes[cid] is undefined a Java script issue on latest version of Mozilla, am beginning to think there are corrupt files as also cannot access "Menu" toolbar although it shows briefly if I go to "customise" then "Restore default set" but promptly disappears when I close that tool. I have several toolbars selected (Right click on blank area at top of Firefox window) but they can't be deselected. I can't go into Safe mode and have tried uninstalling and reinstalling but to no avail.

Anyone got any ideas what to try next?

For the toolbars (customize) problem see:

• http://kb.mozillazine.org/Corrupt_localstore.rdf

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

quicknote 0.6.0.8 was my problem. disabled and removed. problem solved.

On my laptop, the culprit was "OneClick YouTube Downloader", version 1.0.6. I believe it came with Orbit Downloader, a standalone app. Once I disabled this addon, the error went away.

another update....another new problem!

why don't you guys slow down a bit & test this stuff out before you release it??!!

i'd love to see which add on might be the culprit, but firefox won't load the page with my add ons...

any comment?

I agree. This problem has continued to bug me for a couple of weeks now. I cannot uninstall my plug-ins, as some of them act as virus protection (noScript)...others I use constantly. This is the first time I've had an issue with FF. HURRY UP AND MAKE ANOTHER VERSION. I tried to reinstall it to no avail. Apparently this error is common with this release. Next step for me will be to find a lower version release - 9 maybe...

Locking this post, please start a new thread if you need additional help.

-Michelle