Fix slowness, crashing, error messages and other problems

• Fix problems with websites (Facebook, YouTube, webmail etc.)
• Unblock Firefox from connecting to the Internet
• Procedures to diagnose and fix problems
• Videos, sound, pictures and animations don't work
• Firefox is slow or stops working Slowness or hanging
• Firefox crashes Crashing
• Firefox won't save settings or remember information
• Problems with add-ons, plugins or unwanted software
• Refresh Firefox - reset add-ons and settings Restore Firefox to its default settings while saving essential data. This can fix slowness, crashing, search hijacking and other problems.
• How to troubleshoot the error code "SEC_ERROR_UNKNOWN_ISSUER" on secure websites This article explains why you might see the error code "SEC_ERROR_UNKNOWN_ISSUER" on HTTPS websites and how you can troubleshoot it.
• Accessibility not available during multi-process support Accessibility features are not yet fully supported in multiprocess Firefox. Restart Firefox to change it back to single process mode.
• How to troubleshoot time related errors on secure websites This article explains why you might see time-related errors on HTTPS websites and how you can troubleshoot them by correcting your system clock.
• Firefox Health Report - understand your browser performance Firefox Health Report lets you know how well your browser is performing and what steps you can take to improve it.
• What do the SSLv3 error messages mean on Firefox? When accessing a site with SSLv3, Firefox will block it and display an "Unable to connect securely" message.
• Avoid and report Mozilla tech support scams Mozilla does not charge for software, upgrades or technical support. Find out about common scams and how to protect yourself from them.
• Allow Firefox to load multiple tabs in the background The menu option to allow Firefox to load multiple tabs simultaneously has been removed in version 47 and over. Learn how to change this setting in about:config.
• Pages appear tiny when I print or view them in Print Preview How to work around a known issue that causes pages to print or appear very small in Print Preview.
• How to reset the default user agent on Firefox Learn how to reset your Firefox "user agent" so that websites can detect your correct browser and version and display the way they should.
• Pre-8.1 versions of Websense cause startup crashes in Firefox There is a known issue with Forcepoint Websense that causes startup crashes in Firefox.
• Hardware acceleration and WindowBlinds causes Firefox to crash There is a known issue with WindowBlinds and hardware acceleration that causes crashing in Firefox. Here are some workarounds you can try.
• My Mac won't shut down after updating to Firefox version 45 Some Mac users are unable to shut down their computers after updating from Firefox version 44 to 45. Learn how to shut down your computer using Terminal.
• Norton Toolbar won't work with Firefox version 41 Norton Toolbar and Identity Safe uses old, unstable technology called "Binary XPCOM" that's not compatible with the latest Firefox version. Learn to stay safe.
• Streaks, smeared lines or blurry web pages while scrolling on Firefox How to fix an issue that causes images and text to display as smeared or streaky lines or tears while scrolling before the update is available.
• Lastpass was disabled after updating Firefox How to enable Lastpass after updating to the latest version of Firefox.
• Rate your Firefox experience (Heartbeat) As you use Firefox, you may be selected to rate your experience. Your feedback helps us understand your needs so we can act on them quickly.
• Recover lost bookmarks on Firefox Developer Edition Learn a simple method for running both Firefox Developer Edition and standard Firefox versions without losing your bookmarks.
• Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work? Beginning in version 52, Firefox no longer loads NPAPI plugins except Adobe Flash. Find out how it works and what you can do about it.
• Firefox crashes - Troubleshoot, prevent and get help fixing crashes Learn how to troubleshoot and fix Firefox crashes, and find out how to get more help if you're having problems solving the issue.
• What to do when searches take you to the wrong search website Firefox searches going to the wrong website can be caused by your Internet provider, an add-on, toolbar or malware. Learn how to fix this.
• Firefox repeatedly opens empty tabs or windows after you click on a link This article covers a number of fixes you can try if this is happens to you.
• Firefox is stuck in Safe Mode This article describes why Firefox may start in Safe Mode when you expect it to start normally and how to fix the problem.
• Reset your Master Password if you've forgotten it You can reset your Firefox master password if you've forgotten it. Careful: This will remove all of your saved usernames and passwords.
• Fix video and audio playback problems on Firefox for Windows If Firefox has trouble playing video or music on a Windows computer, you can install the Media Feature Pack, if it's missing. Learn more.
• Wrong home page opens when I start Firefox - How to fix Learn how to restore your home page if a third-party software vendor changes it so that their page always opens when you launch Firefox.
• Avoid crashes - Tips and tricks Here are some easy things you can do to avoid crashes and keep Firefox running in tip-top shape.
• Problems with email and how to find help Find out the right direction to get help using webmail in Firefox and links to support pages for popular web-based email services.
• How do I submit a bug for Firefox sync? Submitting a bug for sync? Please include these details.
• Fix printing problems in Firefox Learn how to troubleshoot and fix printing problems in Firefox.
• Firefox keeps crashing at startup If Firefox keeps crashing when you try to start it and other solutions don't work, a clean reinstall can often fix the problem.
• Home page with pipe character opens extra tabs when Firefox starts Set up Firefox to open multiple home pages replacing the pipe character (|) with %7C.
• Can't add, change or save bookmarks - How to fix This article shows you what to do if you cannot add new bookmarks or make other changes to your bookmarks.
• Navigation buttons like back, home, bookmarks and reload are missing If these or other Firefox toolbar items are missing, this article will show you how to restore them.
• How to run Firefox when your profile is missing or inaccessible How to fix the error ''Your Firefox profile cannot be loaded. It may be missing or inaccessible'' so that you can start and run Firefox.