On the Extensions section of the Add-ons page, the disabled extensions cluster at the bottom. I don't know whether you scrolled all the way down to check whether Webroot is there and needs to be enabled.

Either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then check toward the bottom. Anything?

If it's nowhere to be found, could you open Webroot and see whether its settings have a way to turn browser add-ons on and off? You could try turn them off and on again and see whether Webroot pushes the add-on back into Firefox.

Any luck?

DBEAK said

I had Webroot as a password manager inside of Firefox and its disappeared. I can not find a way to get it back.

Nothing has worked. I am wondering if maybe Lastpass has caused the Webroot system to be eliminated. The Webroot system was a lot like Lastpass so maybe Lastpass has done something to eliminate this competitor's system of password management. I think that is probably why its gone, Lastpass must have somehow eliminated Webroot's password manager plugin. I plan to give up now.

If you prefer Webroot, you might submit that question to their support, whether LastPass could have disabled it.