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- How to Fix Disable Firefox Sync Firefox uses too many CPU resources - How to fix Websites say that Firefox is outdated or incompatible even though it's the latest version Firefox does not work - Common fixes to get you back up and running Memory constraints, Firefox performance and Firewalls Rate your Firefox experience, surveys and out of date messages (Heartbeat) How to resolve weak crypto error messages on Firefox 64-bit Firefox crashes with Citrix's XenApp VM How to fix an error when trying to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