This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Buscar en Ayuda

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Downloaded the 11.0 version of Mozilla Firefox to replace old version 9.0. After installation, and on the first launch attempt, received a message: "MOZCRT.dll missing" I researched, tried the prescribed remedy below, to no avail. Please advise.

  • 1 respuesta
  • 7 tienen este problema
  • 2 visitas
  • Última respuesta de cor-el

more options

Here is the unsuccessful solution I attempted (3 times):


Download a fresh Firefox copy and save the file to the desktop. Firefox 11.0.x: http://www.mozilla.com/en-US/firefox/all.html

Uninstall your current Firefox version, if possible. Do NOT remove personal data when you uninstall the current version or you lose your bookmarks and other data in the profile folder.

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

Here is the unsuccessful solution I attempted (3 times): Download a fresh Firefox copy and save the file to the desktop. Firefox 11.0.x: http://www.mozilla.com/en-US/firefox/all.html Uninstall your current Firefox version, if possible. Do NOT remove personal data when you uninstall the current version or you lose your bookmarks and other data in the profile folder. Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

Todas las respuestas (1)

more options

Which security software (firewall, anti-virus) do you have?

If you use ZoneAlarm Extreme Security then disable Virtualization and reinstall Firefox.
Other security software may have similar features to prevent Firefox from updating files properly.

See these pages for a similar issue with corrupted files: