We're sorry to hear that your Firefox seems to be crashing when you open it. 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. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Try to start Firefox in Safe Mode by holding down the Shift (Mac: Options) key to see if that helps.

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

See also:

• http://kb.mozillazine.org/Firefox_crashes
• https://support.mozilla.org/kb/Firefox+crashes

Did you remove the Firefox program folder before reinstalling Firefox?

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

• Download the Firefox installer and save the file to the desktop
  https://www.mozilla.org/en-US/firefox/all/

If possible uninstall your current Firefox version to cleanup the Windows registry and settings in security software.

• Do NOT remove "personal data" when you uninstall your current Firefox version, because this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you uninstall and (re)install or update Firefox, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

These are my last five error reports. Crash ID: bp-74096b8f-a3f7-432c-a1a0-767212160214 Crash ID: bp-68652547-8f48-4a36-a9b3-a83152160213 Crash ID: bp-008b7c90-8159-4afe-99d0-f07872160213 Crash ID: bp-bd821ef9-bb7f-4c8a-8eb7-bcc242160213 Crash ID: bp-4ecce8d6-0c5f-42f2-80c5-fdf002160213

I tried a clean reinstall, deleting the Firefox folder and that did not work.

thanks - unfortunately this crash may be caused by websense endpoint security software that is running on a device. in case your computer is part of a managed enterprise environment, please get in contact with your it department about this issue. more information is available in bug 1181091.

in a larger enterprise using the extended support release (esr) version of firefox, which receives security updates but feature updates only once every 10 months, might also be a better option compatibility-wise: https://www.mozilla.org/en-US/firefox/organizations/faq/