Actually the message says the Norton toolbar version you have is incompatible with Firefox 12.0.

http://community.norton.com/t5/Norton-Internet-Security-Norton/Firefox-12-Support-for-Norton-Toolbar/td-p/704071

http://community.norton.com/t5/Norton-360/Firefox-12-Support-for-Norton-Toolbar/td-p/704079

from Firefox 10, thirdparty addon are disable by default.

• go to Firefox/Tools>Add-ons>Extension (CTRL+SHIFT+A), make sure all Norton extension are enable?

So from reading the links James provided it sounds like if you update your other Norton software your toolbar will be compatible as well. Can anyone confirm this? We still seem to be getting reports of this issue even though it sounds like Norton has addressed it.

Yes Matt all symantec products are compatible ith Firefox 12 currently

I just received a Symantec update earlier this week, and that's when my Norton Toolbar went away. I uninstalled and reinstalled norton to no avail. 5/10/12

Go through the links James provided in his first reply.

Also see this -> http://community.norton.com/t5/Norton-Internet-Security-Norton/Product-Update-19-7-for-Norton-Internet-Security-2012-and-Norton/td-p/703501

Check and tell if its working.

After uninstalling Norton, apparently, I didn't run live update enough times. All appears to be okay now. Thanks.

You are welcome !