Starting with version 41, Firefox has stopped supporting an old and fairly unstable technology called "Binary XPCOM" used by a small number of add-on developers. Mozilla has encouraged developers to update their add-ons in order to stay safe and compatible with the latest versions of Firefox (see the Mozilla blog post here and also our article Add-on signing in Firefox).
The current Norton Toolbar is temporarily not fully functional with Firefox until Norton releases a major upgrade. Norton's planning is announced on their forum including Norton's initial announcement and latest status updates).
Steps you can take:
- The standalone Norton application will continue to work without the toolbar. Use the features within the Norton application and if necessary uninstall the toolbar. Reinstall it when Norton releases a fix.
- Continue using the latest version of Firefox for the most stability and security. Do not use an older version of Firefox.
- Identity Safe users: Use Identity Safe directly in your Norton product, or visit https://identitysafe.norton.com/ in a new tab. From your Norton product or the Identity Safe site, you can view your logins and copy/paste your usernames and passwords. You can also access your address and wallet items.