Firefox doesn’t start because Xul.dll Was Not Found

Mozilla Firefox Errors, Xul.dll

Xul.dll Was Not Found

The Xul.dll file in Mozilla Firefox plays an important role in the browser’s functioning. When you try to start the Firefox browser, it crashes and displays error messages. Such issues are caused from conflicts that occur between third party programs and damage from malware. Troubleshooting the xul.dll Mozilla Firefox errors quickly and safely maximizes Mozilla Firefox Web browsing.

Symptoms for the error

If Firefox has crashed and is incapable of launching, the “xul.dll not found” error message pop ups on the screen When you double-click the Firefox icon. If the xul.dll file that controls and improves Web browsing speed is missing, damaged or corrupt, such type of errors crops up in Firefox.

Causes for the Mozilla Firefox errors

For Firefox to run properly, xul.dll is very necessary file. When you install the browser, it’s automatically installed. Malware, such as Trojans and viruses can cause severe Damages to the file. If Firefox isn’t on the application’s list of programs allowed to connect to the Internet, firewalls and antivirus programs may also prevent the file from executing.

Reinstalling Firefox

Uninstalling Firefox and reinstalling a fresh copy re-installs the missing file if the xul.dll error message continues to pop up. From your computer’s Control Panel, if you open “Programs and Features“, Windows displays a list of installed programs. Click “Firefox” and to remove the browser from your computer, click the “Uninstall” button. In Windows Explorer, remove its setup folder from the Program Files folder after uninstalling the browser to delete user settings. Download the latest version of Mozilla Firefox When the uninstall process completes.


The risk of running into xul.dll error messages are decreased by adding Firefox to a firewall or antivirus program’s list of applications that are allowed to connect to the Internet. This process however varies with different security tools, so for setup information, refer to

Mozilla Firefox Errors, Xul.dll

Xul.dll Was Not Found

your program’s documentation.

Some Tips

Malware often causes damages to the xul.dll file, so it is advised to run the antivirus and spyware tools occasionally. Run system scans to delete malware if Firefox is already on your security program’s list of applications allowed to access the Internet. Also get the latest virus definition lists and security updates through Security programs’ updates.

That’s all there is to it, thank you for your time, have a great day!

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>