Troubleshoot Firefox issues caused by malware
Malware is short for "Malicious Software". It is a term generally used for software installed on your computer that is designed to infiltrate or damage a computer system without the owner's informed consent. Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of. This article describes what common symptoms are and how to prevent malware from being installed and get rid of them.
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How do I know that my Firefox problem is a result of malware?
Symptoms are various and depend on the malware but if you have one or several of these behaviors, you may have malware installed on your computer.
- Some ad popups display all the time, although you've blocked popups. For more information on blocking popups, see Pop-up blocker.
- Your searches are redirected to another site in order to feed you content from that website and you are being disallowed from blocking them. For more information, see Searches are redirected to another site.
- Your home page has been hijacked. For more information on setting your home page, see How to set the home page.
- Firefox never finishes loading or can not load certain websites. For more information, see Firefox never finishes loading certain websites and Firefox cannot load certain websites.
- Firefox crashes or hangs a lot. For more information, see Firefox crashes and Firefox hangs.
- Firefox does not start. For more information, see Firefox will not start.
- Problems with connecting to Facebook. For more information on problems with Facebook, see Problems using Facebook in Firefox.
- Firefox keeps opening many tabs or windows. For more information, see Firefox keeps opening many tabs or windows.
- Unwanted toolbars have been installed. For more information on customizing Firefox, see How do I customize the toolbars? and Customizing Firefox with add-ons.
How do I prevent malware from being installed?
There are simple rules to follow in order to prevent malware from being installed on your computer:
- Keep your operating system and other software updated: Installation of malicious software usually takes advantage of known security vulnerabilities in other programs, which may have been patched in later versions. Make sure you are using the latest version of each piece of software you use, including plugins using Mozilla's plugincheck website and Windows using the Windows Update feature.
- Don't install untrusted software: Some websites offer you software to accelerate your browser, to help you search the Web, to add toolbars that make things Firefox already does. Some unwanted programs also come bundled in software packages. Usually, these programs gather information on your browsing behavior that serve only people who designed them and interfere with Firefox. Make sure you install add-ons from Mozilla's add-on website and you uncheck unwanted programs in software wizards.
- Don't click inside misleading pop-up windows: Many malicious websites try to install malware on your system by making images look like pop-up windows, or displaying an animation of the website scanning your computer. For more information on detecting a misleading pop-up, see Pop-up blocker.
- Run anti-virus and anti-spyware real-time protection and scan your system periodically. Make sure your anti-virus and anti-spyware real-time protection is enabled. Scan your computer at least every month.
- Don't run a fake Firefox: Download Firefox from mozilla.com.Note: Please report misuse of the Firefox trademark in websites using the Mozilla's Violating Website Report page and in emails by forwarding them to Mozilla's abuse email.
How do I get rid of malware?
If your anti-virus and anti-spyware software hasn't detected malware, scan your system with other free malware scanning programs. You need to scan with all programs because each program detects different malware and make sure that you update each program to get the latest version of their databases before doing a scan.
If Firefox opens multiple tabs or windows with unwanted content or crashes at startup, try also:
If the problem still continues, ask for help in specialized forums for malware removal such as those listed below:

Firefox Help