Hello,

Try Firefox Safe Mode to see if the problem goes away. Firefox Safe Mode is a troubleshooting mode that turns off some settings and disables most add-ons (extensions and themes).

(If you're using an added theme, switch to the Default theme.)

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu by clicking on the Restart with Add-ons Disabled... menu item:


If Firefox is not running, you can start Firefox in Safe Mode as follows:

• On Windows: Hold the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac: Hold the option key while starting Firefox.
• On Linux: Quit Firefox, go to your Terminal and run firefox -safe-mode
  (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in 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 to find the cause.

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help others with the same problem.

Thank you.

Trouble is, I cannot open Firefox when a version over 15.0.1 is installed, even holding the shift key to start in safe mode.

Hi kayelena, Sorry we seem to have overlooked your reply.

You say Firefox will not run, but also that you get a not responding message and must Kill Firefox in the Task Manager.

You may not be seeing much but Firefox appears to be running or attempting to run. Please attach a screen shot of the error message.

• How to make screenshots
• How do I create a screenshot of my problem?

Maybe checking the Windows event logs will throw some light on what is happening.

• See also Firefox won't start - find solutions
• http://windows.microsoft.com/en-gb/windows/what-information-event-logs-event-viewer#1TC=windows-7

A possible cause is security software (firewall,anti-virus) that 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

Which of the event logs do you need to see?

I followed the directions to add Firefox to the list in Windows Firewall. Still having the same problem. I'm not certain what happened, but Firefox must have updated itself, because even though I reverted back to the earlier version, it won't run again today. I clicked on the icon and after about five minutes the Firefox screen appeared, but I cannot do anything with it. I am attempting to send you a screen shot of what I see. Hope it works.

We can see that Firefox is open, your screenshot is part of the Firefox Window.

Try again with the current Release, version which at present is Firefox 26. As cor-el said try

• Configure firewalls so that Firefox can access the Internet
  • And if you only have the standard Window7 Firewall then see
    How to let Firefox use the internet on your Windows computer

You will probably have to set the Firewall whilst the current Release is installed.

I re-installed Firefox 26 and reset Windows Firewall. Firefox loaded and ran just fine through the afternoon, even after re-booting the computer several times as a test. Now this evening, I tried to run Firefox and it would not open. I am attaching a screen shot of the error.

hello kayelena, in this thread some other affected users have reported that the problem might be related to the fingerprinting software on their pc: https://support.mozilla.org/en-US/questions/980011

edit: for indexing purposes i'll reference the unresponsive script in the error message:

chrome://browser/content/tabbrowser.xml:2406

I note the thread philipp refers to suggests disabling the fingerprint reader as a test or workaround, and also mentions updating the software may solve the problem

mykalwebs
/questions/984124#answer-525249

Fixed it by updating the "Lenovo Fingerprint Read/Password Vault for Windows" driver and software to version 6.0.200.105 date 2 Sep 2013. 

 If you need to determine the "Machine Type" and "Model" for you Lenovo laptop go to: Start->All Programs->Accessories->System Tools->System Information : "System Model". For my Thinkpad Edge E530 the first 4 digits were the Machine Type, the last 3 digits were the Model. 

 I had previously disabled the fingerprint reader:
 Start->Control Panel->Hardware and Sound->Biometric Devices->Change Settings : "Biometrics Off" 

I disabled the Lenovo fingerprint reader. The problem still persists. I ran HitmanPro. No threats were found; only some tracking cookies. Today, Firefox takes about 10 minutes to open and then goes into error mode. Attached is a screen shot from today's session. I'm thinking that this is wasting your time and mine. Google Chrome and Internet Explorer both give me no trouble. Maybe I will wait until Firefox issues a new update. There clearly, to me, is an issue with Firefox's update rather than my computer. Firefox 15 ran without any trouble.

Sorry you are still having this problem. The specific error message on a Lenovo has previously been noticed and reliably attributed to use of the Fingerprint reader.

I think first of all as a troubleshooting method we should temporarily remove as many of the elements that could cause problems.

Try all of this

• Firefox in offline mode (Firefox Button -> Web Developer -> Work Offline )
• Disable the Firewall and any Security related software
• Use Firefox's Safemode (e.g. Hold Shift Key when starting)
• Disable all Firefox Addons
• Disable the Lenovo Fingerprint Reader

Note also that an alternative method of looking at error messages is to use the Error Console

• Use Firefox Button -> Web Developer -> Browser Console
• That allows filtering to see only error messages, and clearing of earlier messages.

My hope is that Firefox will work in the configuration as above and by a process of elimination we will quickly find the problem.