Hi,

Are you facing this problem out of nowhere? Or does it happen after you install additional extensions?

Please check if solutions from here help: https://support.mozilla.org/en-US/kb/warning-unresponsive-script

You might check this articles for clues: http://kb.mozillazine.org/Problematic_extensions http://kb.mozillazine.org/Unresponsive_Script_Warning http://kb.mozillazine.org/Script_busy_or_stopped_responding http://kb.mozillazine.org/Firefox_hangs

Cheers!

The problem is there without any extensions added by me. As I said, FF won't start in safe mode. Or rather, it will start after about 5 mins but immediately becomes unresponsive. I can't try turning off hardware acceleration because there is no way to access working controls. But it was working yesterday with the same set up as today.

Oh, OK. Gotcha.

Have your tried following below steps:

1. Clear cache
2. Exit Firefox
3. Go to your profile folder (http://kb.mozillazine.org/Profile_folder_-_Firefox )
4. Delete all sessionstore.js
5. Restart Firefox

?

Well he won't be able to do steps #1-2 b/c his Firefox keeps freezing as soon as he opens it. Is that right? Or can you use Firefox for a little while before it freezes?

If he deletes his sessionstore.js that will delete all his saved tabs & windows. But it's a good point. How many tabs & windows do you have open when you start Firefox? It's fine if you guess. Maybe 20 or 30 tabs? In case deleting this file doesn't solve the problem, backup it to another location before deleting it. That way you can restore it later on.

Honestly, the problem sounds like one of your addons is broken b/c of the new Firefox update and causes Firefox to freeze on startup.

To test my theory out, here's a link to download the previous Firefox version:
Firefox 20 download

If that works, next we'll need a list of your addons. You can quickly copy a list of your addons from Firefox button > Help > Troubleshooting Information. Then click the "Copy text to clipboard" button.

Then come back here and paste the info.

Here's a article about that:
https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox

Installed the earlier version of FF and it works.

Here is the list of addons

 Application Basics

       Name
       Firefox

       Version
       20.0.1

       User Agent
       Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0

       Build Configuration

         about:buildconfig

 Extensions

       Name

       Version

       Enabled

       ID

       DownThemAll!
       2.0.16
       true
       {DDC359D1-844A-42a7-9AA1-88A850A938A8}

       Greasemonkey
       1.8
       true
       {e4a8a97b-f2ed-450b-b12d-ee082ba24781}

       RoboForm Toolbar for Firefox
       7.8.9.5
       true
       {22119944-ED35-4ab1-910B-E619EA06A115}

       Session Manager
       0.8.0.6
       true
       {1280606b-2510-4fe0-97ef-9b5a22eafe30}

       1-ClickWeather
       1.1.9.1
       false
       {DCBD1271-D228-4082-9FBC-36D9B7660B03}

       Norton Toolbar
       2013.3.5.1
       false
       {2D3F3651-74B9-4795-BDEC-6DA2F431CB62}

       Norton Vulnerability Protection
       11.3.0.9 - 5
       false
       {BBDA0591-3099-440a-AA10-41764D9DB4DB}

       Personas Plus
       1.7.2.1
       false
       personas@christopher.beard

       recipefox
       0.63
       false
       {EA6F5510-6F4D-11DC-B4DA-1B6D56D89593}

       SeoQuake
       2.8.11
       false
       {317B5128-0B0B-49b2-B2DB-1E7560E16C74}

       Symantec VIP Access Add-On
       2.0.5.0
       false
       VIP5X@verisign.com

 Important Modified Preferences

     Name

     Value

       browser.cache.disk.capacity
       358400

       browser.cache.disk.smart_size.first_run
       false

       browser.cache.disk.smart_size.use_old_max
       false

       browser.cache.disk.smart_size_cached_value
       358400

       browser.places.smartBookmarksVersion
       4

       browser.startup.homepage_override.buildID
       20130409194949

       browser.startup.homepage_override.mstone
       20.0.1

       dom.mozApps.used
       true

       dom.w3c_touch_events.expose
       false

       extensions.lastAppVersion
       20.0.1

       gfx.direct3d.prefer_10_1
       true

       network.cookie.prefsMigrated
       true

       places.database.lastMaintenance
       1369147808

       places.history.expiration.transient_current_max_pages
       96731

       plugin.disable_full_page_plugin_for_types
       application/pdf

       privacy.sanitize.migrateFx3Prefs
       true

 Graphics

       Adapter Description
       Intel(R) HD Graphics 4000

       Adapter Drivers
       igdumdim64 igd10iumd64 igd10iumd64 igdumdim32 igd10iumd32 igd10iumd32

       Adapter RAM
       Unknown

       Device ID
       0x0166

       Direct2D Enabled
       Blocked for your graphics driver version.

       DirectWrite Enabled
       false (6.2.9200.16492)

       Driver Date
       3-19-2013

       Driver Version
       9.18.10.3071

       GPU #2 Active
       false

       GPU Accelerated Windows
       1/1 Direct3D 9

       Vendor ID
       0x8086

       WebGL Renderer
       Google Inc. -- ANGLE (Intel(R) HD Graphics 4000)

       AzureCanvasBackend
       cairo

       AzureContentBackend
       none

       AzureFallbackCanvasBackend
       none

 JavaScript

       Incremental GC
       true

 Accessibility

       Activated
       true

       Prevent Accessibility
       0

 Library Versions

       Expected minimum version

       Version in use

       NSPR
       4.9.5
       4.9.5

       NSS
       3.14.3.0 Basic ECC
       3.14.3.0 Basic ECC

       NSSSMIME
       3.14.3.0 Basic ECC
       3.14.3.0 Basic ECC

       NSSSSL
       3.14.3.0 Basic ECC
       3.14.3.0 Basic ECC

       NSSUTIL
       3.14.3.0
       3.14.3.0

Spoke too soon. FF worked for a day, after rolling back. But now it goes unresponsive again as soon as I open it.

I have the same problem. If I uninstall FF, delete all folders, download and install, FF works until I turn off the laptop. Upon restart FF does exactly the same as above.