since the last update it is no longer heard on youtube

If the problem is only in Firefox and audio works correctly in other browsers such as Chrome, the issue is usually related to Firefox audio settings, extensions, hardware acceleration, or corrupted media settings after an update. Please try the following steps: 1) Check Firefox Volume in the System Mixer. Sometimes Firefox becomes muted separately in the operating system. - Play a YouTube video in Firefox - Open the system volume mixer - Make sure Firefox is not muted and the volume is turned up 2) Test in Troubleshoot Mode - Open the Firefox menu - Go to Help → Troubleshoot Mode - Restart Firefox and test YouTube audio again If sound works there, an extension or custom setting is causing the issue. 3) Disable Hardware Acceleration - Go to Settings → General - Scroll to Performance - Uncheck “Use recommended performance settings” - Uncheck “Use hardware acceleration when available” - Restart Firefox 4) Clear YouTube Site Data - Open YouTube - Click the padlock icon in the address bar - Select “Clear cookies and site data” If the issue continues, please provide: * Your operating system and version * Firefox version * Whether all websites are affected or only YouTube * Whether the issue also occurs in a private window or Troubleshoot Mode