Try the Firefox Safe Mode to see how it works there. The Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open the Firefox 4.0+ Safe Mode by holding the Shift key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Don't select anything right now, just use "'Start in Safe Mode" To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shift key) to open it again. If it is good in the Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one.

Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thanks for getting back to me.

Just tried opening it in Safe Mode a few times - exactly the same problems - still asks me if I want to contribute every time and still crashes when trying to upload files.

Home page seems to have been remember now though - but this has fixed itself on 'normal mode' too.

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, Open websites, and some Preferences.

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!

We're sorry to hear that your Firefox seems to be crashing. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. Enter about:crashes in the Firefox location bar (that's where you enter your website names) and press Enter. You should now see a list of submitted crash reports.
2. Copy the most recent 5 report IDs that you see in the crash report window and paste them into your forum response.

Thanks in advance for your help!

More information and further troubleshooting steps can be found in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Afraid, that the reset feature does nothing to help.

No crashes appear on that page. When it does 'crash' it freezes, then shuts down after a couple of seconds, leaving no error message.

Cheers.

Are the related telemetry prefs saved in prefs.js?

• user_pref("toolkit.telemetry.prompted",2);
• user_pref("toolkit.telemetry.rejected",true);

(the latter may not be there)

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder

If you do not keep changes after a restart then see:

• http://kb.mozillazine.org/Preferences_not_saved

Which security software (firewall, anti-virus) do you have?

Some security software has virtualization or sandbox features that may cause problems by protecting and restoring files in the Firefox profile folder.

Neither of those lines appear in the prefs file.

I have reset that file by forcing FF to create a new one, but it still does the same asking me about if I want to send data every time. Also still won't remember my home page. (it doesn't open the Firefox Updated tab though, just the FF start page)

I have Microsoft Security Essentials.

The second is issue about uploading files has now been fixed - not sure what did it but that's all OK now.

Did you check for problems with saving prefs?

• http://kb.mozillazine.org/Preferences_not_saved

Do you have any numbered prefs-##.js files in the Firefox Profile Folder?

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder

No other pref files. Have none of those other programs it suggests. No user.js file. prefs.js is uncorrupted and writable. I haven't installed any extensions/addons to FF

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

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

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.

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

I thought I'd done this already, but I've just given it another go and it's worked!

Many thanks for all your help.