Download Firefox Systems and Languages What's New Privacy Performance and connectivity Deal with error messages, crashing applications, connectivity issues, and slow performance. ទាំងអស់ All articles and threads Crashing and slow performance Site breakages Connectivity Error codes In English Secure connection failed and Firefox did not connect How to troubleshoot time related errors on secure websites Website will not allow Firefox to display the page if another site has embedded it Connection settings in Firefox Fix "The bookmarks and history system will not be functional" error message Captive portal detection Diagnose Firefox issues using Troubleshoot Mode Firefox uses too much memory or CPU resources - How to fix What do the security warning codes mean? Troubleshoot and diagnose Firefox problems Resist Fingerprinting Firefox can't load websites but other browsers can Task Manager - see whether tabs or extensions are slowing down Firefox DNS over HTTPS (DoH) FAQs Warning Unresponsive script - What it means and how to fix it How do I report a broken site in Firefox desktop? Firefox hangs or is not responding - How to fix Firefox DNS over HTTPS How to let Firefox use the internet on your Windows computer Use the Troubleshooting Information page to help fix Firefox issues How to reset the default user agent on Firefox Disable Firefox Sync HTTPS-First upgrades to secure connections How to fix the Update Failed error message when updating Firefox Server Not Found - Troubleshoot connection problems Certificate contains the same serial number as another certificate Where to go for developer support Unload inactive tabs to save system memory in Firefox Firefox blocked by macOS 15 Sequoia firewall - What you need to know Websites look wrong or appear differently than they should Quick fixes if your Firefox slows down "Firefox is already running but is not responding" error - How to fix Firefox does not work - Common fixes to get you back up and running Rate your Firefox experience, surveys and out of date messages (Heartbeat) How to troubleshoot security error codes on secure websites Drag and Drop errors with Firefox Launcher Process enabled and Windows UAC disabled - How to Fix Solutions for "Can not create temp folder archive" error when installing Firefox (Windows 10) Firefox takes a long time to start up Firefox says it's just updated every time it starts - how to fix X-Mouse Button Control in Firefox 110 Firefox uses too many CPU resources - How to fix Websites say that Firefox is outdated or incompatible even though it's the latest version Memory constraints, Firefox performance and Firewalls How to resolve weak crypto error messages on Firefox 64-bit Firefox crashes with Citrix's XenApp VM How to fix an error when trying to open Telegram or Slack on Firefox Identify problems caused by third-party modules in Firefox for Windows Difficulties opening or using a website in Firefox 100 Firefox hangs when copying with Suggested Actions enabled on Windows 11 - What to do Address screen sharing issues with Firefox on macOS 15 Sequoia Bug 1931078 Troubleshoot Firefox crashes (closing or quitting unexpectedly) Firefox is stuck in Troubleshoot Mode Firefox repeatedly opens empty tabs or windows after you click on a link Avoid crashes - Tips and tricks Firefox keeps crashing at startup Fix video and audio problems on Firefox for Windows N editions Problems with email and how to find help Home page with pipe character opens extra tabs when Firefox starts How to run Firefox when your profile is missing or inaccessible