Now - see this: https://community.norton.com/en/blogs/product-update-announcements/firefox-37-support-norton-toolbar

Thank you for your speedy response. You made my life easier.

If you think there is still an issue, it may be caused be a bad registry entry.

Thank God! I hate it when Firefox updates and Norton Toolbar, ID Vault, shows INCOMPATIBLE!!! I don't update FF when this happens.....

lsdevar said

Thank God! I hate it when Firefox updates and Norton Toolbar, ID Vault, shows INCOMPATIBLE!!! I don't update FF when this happens.....

You have to do liveupdate in Norton. Unlike with most extensions, the ones provided to work with a application needs to be updated for each new major Firefox Release.

Norton has had updates for their toolbar within a couple days of Firefox Release ever since Firefox 5.0