Hi, Please check if this happens in [https://support.mozilla.com/en-US/kb/Safe%20Mode Safe Mode]. Safe mode disables the installed '''Extensions''', and themes ('''Appearance''') in '''Tools''' ('''Alt''' + '''T''') > '''Add-ons'''. Hardware acceleration is also temporarily disabled - the manual setting is '''Tools''' > '''Options''' > '''Advanced''' > '''General''' > [https://support.mozilla.org/en-US/kb/Options%20window%20-%20Advanced%20panel?as=u '''Use hardware acceleration when available''']. All these settings/options/add-ons can also be individually or collectively disabled/enabled/changed in Firefox normal mode to check if an extension, theme, option or hardware acceleration is causing issues. Disabling/enabling hardware acceleration, and some types of add-ons in normal mode may require a Firefox restart. [http://support.mozilla.com/en-US/kb/Uninstalling+add-ons Uninstalling Add-ons] [http://kb.mozillazine.org/Uninstalling_toolbars Uninstalling Toolbars] [https://support.mozilla.com/en-US/kb/Troubleshooting%20extensions%20and%20themes Troubleshooting Extensions and Themes] [http://kb.mozillazine.org/Problematic_extensions Problematic Extensions] [https://support.mozilla.org/en-US/kb/Options%20window Options]

Try: *https://addons.mozilla.org/firefox/addon/searchreset/ Try to delete search.sqlite and search.json in the Firefox Profile Folder. * http://kb.mozillazine.org/Profile_folder_-_Firefox Do you still see the default search engines in the searchplugins folder in the Firefox program folder? Also check the attributes of the searchplugins folder and make sure that the folder is not hidden or read-only. See also: *http://kb.mozillazine.org/Unable_to_search_or_add_new_engines