Firefox 18 crashes on startup due to malware - how to fix

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Note: This article only applies to Windows.
Note: This article only applies to Firefox 18.

If you've updated to Firefox 18 and it now crashes on startup it could be due to malware installed on your computer. We'll explain how to get rid of the malware which will let Firefox run normally.

Install and run Microsoft Safety Scanner

  1. Download Microsoft Safety Scanner
  2. When the download has finished downloading, open it and follow the instructions. A "Full Scan" is recommended.
  3. Once the scan is complete the malware should be removed from the computer.

Install and run Malwarebytes anti-malware software

  1. Download the free version of Malwarebytes from this page.
  2. When the installer has finished downloading, open it up and follow the instructions.
  3. Malwarebytes should then open automatically and begin updating itself. If it doesn't, double-click the icon that was placed on the desktop or look for it in the Start menu.
  4. Once Malwarebytes is updated, just click the Scan button and follow the instructions.

  5. When you have finished, the malware should be removed from your computer and Firefox will be able to start.
Note: If you are still having problems with crashes, please see this article.