hello, according to norton the toolbar is already compatible with firefox versions including the current release version. please run the norton liveupdate utility repeatedly & until all components are up-to-date (norton toolbar 2015.5.0.113). in addition make sure that the toolbar is enabled under firefox > addons > extension afterwards.

for more information please refer to https://community.norton.com/en/blogs/product-update-announcements/firefox-39-support-norton-toolbar

Try re-installing Norton.

Download the current full installers for your Norton programs and save them.

Download and run the Norton Removal Tool to uninstall your Norton product

After rebooting the computer, run a registry scanner. Then run the installers.

https://support.norton.com

http://community.norton.com/

FredMcD, that is overkill to having the current version of Norton toolbar extension in Firefox and likely to cause more problems.

wemdav said

As above - message is non compatible

Thank you!