From what I have been reading from other posts on this forum, the issue may be caused by the clear history settings.

Press the <Alt Key> to bring up the tool bar. Then Tools > Options > Privacy. The button next to History, select Use Custom Settings.

At the bottom of the page, turn on Clear History When Firefox Closes.
At the far right, press the Settings button. Turn on ONLY Cache and Form And Search History leaving the others off.

Thank you for the recommendation FredMcD, but unfortunately that did not work. Same result as before.

Anyone else have a suggestion? We now have 5 known machines at work with the same problem. On a couple of the machines, going back to Firefox 28 worked. For others, neither will open anymore.

Please help! <crosses fingers>

Did you post this from one of the problem computers?

It could be the work of one of your add-ons, or even add / mal-ware. Look thru your add-ons list and make sure you know what each one is there for. Also, check the programs that are on your computer Windows > Start > Control Panel > Uninstall Programs. Go thru the list and use a web search to check any that you don't know what they are.

Troubleshoot Firefox Issues Caused By Malware {web link}

Just to be sure:

Are you using "Clear history when Firefox closes" to clear any personal data when you close Firefox?

Hello everyone,

I tried all of the above and it did not work. When I uninstall, I've removed all references in the registry to Mozilla, cleared old old leftover folders under C:\WINDOWS\USERS\<USERID>, so it is a virgin install when I do the setup.

We now have 5 PCs experiencing the same issue and none appear to have any fishy malware installed. We use Bit9 which helps detect unwanted applications but no alerts are being presented to us.

Any other ideas?

Thank you for all your input.

Tremoloman

When you cleared the computer, did you remove or rename the main Mozilla folder? C:\Program Files (x86)\Mozilla Firefox

Yes, I deleted everything on the PC referring to Mozilla Firefox.

Folders: C:\Program Files (x86)\Mozilla Firefox C:\Program Files (x86)\Mozilla Maintenance Service C:\Users\<USERID>\AppData\Local\Mozilla C:\Users\<USERID>\AppData\Roaming\Mozilla

Registry: HKLM\SOFTWARE\Mozilla HKCU\\SOFTWARE\Mozilla

Still no luck. Any other ideas?

Just my 2c,not any definite ideas I am afraid.

Looking for others with similar issues is likely to be a problem because the signal will get swamped with references to known issues

• One fixed by a workaround in Firefox 29.0.1 (seer netpredictions)
• And at least one issue relating to hangs on close down, often noticed when History is cleared because of the setting to clear History on closedown.

Have you considered trying ESR at least as a test to see if that works. There is also a possibility that some of the known issues will be addressed in a Beta release later this week.

This article lists the usual reasons for problems

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

It is a standard Firefox build from Mozlla is it, and not something branded or modified ? Where are you getting the downloads from ?

• e.g. http://www.mozilla.org/en-US/firefox/all/

I suppose you have checked security related software is not affecting this. Someone yesterday mentioned Trend Micro security software was flagging the install as malware.

I tried both the stub installer and the full install I obtained from ftp://ftp.mozilla.org/pub/firefox/releases/29.0.1/win32/en-US/

I don't believe security software is the culprit as I've got hundreds of other users with the same image build without this problem. Since I'm not in security I have no way of disabling anti-virus as it is controlled by AD policy.

I love Firefox so I hope a solution can be found.

You ran virus and malware scanners on everything, Yes?

How about whatever is between the computers? A server or what?

Take one computer, and Start Firefox in Safe Mode {web link} In save mode, just poke around. See if you notice a problem.

After, reboot the COMPUTER in safe mode With Network. Poke around. See if you notice a problem.

Let us know what you get.

Thank you for the suggestions. I ran a machine in "safe mode with networking "and Firefox works perfectly. I tried a 2nd machine - same result.

I tried going back to Firefox 28 and even 27, save results. I will try a malware scan later. (I would have tried when I was there but the users are really busy during work hours).

Ran MSCONFIG and found nothing odd in startup. I did try disabling a bunch of items but it made no difference.

I'll likely have to reimage and rebuild these machines. Seems odd only Firefox would act up since all other applications seem fine.

I'll post results of the malware scan when I can get my hands on one of them.

Thanks again everyone for your assistance!

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

It is possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container 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 and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

• https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating

We are running McAfee firewall and antivirus.

Thank you all for your help. At some point I have to wave the white flag and go with the sure fix. I wound up re-imaging all the machines as I had to get them back up and running.

Best regards, Tremoloman

This post talks about mal-ware in the router

https://support.mozilla.org/en-US/questions/1007352