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When loading, "pop-up" says "Cannot read XUL Runner.ini file

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Up until a few weeks ago, Firefox worked great! Then for some reason when I try to start it from the menu page, a "pop-up box" comes on the screen saying it "can't read the XUL Runner.ini file". I've tried deleting Firefox, but I get the can't read the XUL Runner.ini file. I've tried reloading a fresh copy to install but it refuses it install it saying it "can't read the XUL Runner.ini file and the installation failed. I use AVAST Antivirus and no virus has been reported. HELP!

Up until a few weeks ago, Firefox worked great! Then for some reason when I try to start it from the menu page, a "pop-up box" comes on the screen saying it "can't read the XUL Runner.ini file". I've tried deleting Firefox, but I get the can't read the XUL Runner.ini file. I've tried reloading a fresh copy to install but it refuses it install it saying it "can't read the XUL Runner.ini file and the installation failed. I use AVAST Antivirus and no virus has been reported. HELP!

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Some files may have been locked or protected by security software and may have failed to get updated.

  • Download a fresh Firefox copy from http://www.mozilla.com/firefox/all.html and save the file to the desktop.
  • Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer.
  • Don't remove personal data if you uninstall the current version.
  • 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.

Your bookmarks and other profile data are stored elsewhere (not in the Firefox program folder) and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.