Reload the webpage while bypassing the cache *Hold down the ''Shift'' key and click the ''Reload'' button with a left click. *Press ''Ctrl'' + ''F5'' or ''Ctrl'' + ''Shift'' + ''R'' (Windows and Linux) *Press ''Command'' + ''Shift'' + ''R'' (Mac) Clear the cache and the cookies from sites that cause problems. '''Clear the Cache''': Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now" '''Remove Cookies''' from sites causing problems: *Tools > Options > Privacy > Cookies: "Show Cookies" ___________________________________________________________________ Start Firefox in [https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Safe Mode to Troubleshoot the issue] and to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance). * https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes