The Norton Toolbar is now compatible with Firefox 25. We have released a Firefox 25 compatibility patch for Norton Internet Security 21.1.0.18, 21.0.1.3, 21.0.0.100, 20.4.0.40 and 19.9.1.14 which is available via LiveUpdate. Please see the Firefox 25 Compatibility Update announcement for version details and troubleshooting any problems with the update.
Cheers,
Sunil G A
Norton Forums Administrator
Symantec Corp.