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Does it still happen in Troubleshoot Mode?

Thank you for your reply. Clearing cookies and disabling tracking protection did not help. It does not happen in troubleshoot mode, but posts are slow to load.

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

If it works in Troubleshoot Mode and in regular mode with all extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) disabled, try to find which extension is causing the problem by enabling one extension at a time until the problem reappears.

You can use the Restart button on the about:profiles page after each change to restart Firefox. You can open "about:" pages via the location/address bar.

If the problem doesn't happen in troubleshoot mode, the most likely cause is a theme or extension - see the second article linked in the previous reply.

See also

https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_the-problem-does-not-happen-in-troubleshoot-mode

Try disabling your extensions.

Kaspersky can cause performance issues if you have "Inject script into web traffic to interact with web pages" enabled and don't have the companion browser extension installed.

Thank you for your help. We found an extension that was causing the problem -Adblock Plus. We changed the settings on it and so far my Facebook news feed is stable.