I just did disabled in Norton after this nasty toolbar crept up again. I thought I disabled it by going into outlook\tools\trustcenter\addin\manage com in. It disables the Norton Antispam toolbar until I reboot and it comes back.
I use Win 7 and Norton Security Suite, v 20.2. Before I check you off for best answer, I want to ask if I disable in Norton, do I sacrifice all protection all antispam protection. My guess is that outlook has some antispam feature, though likely not as robust as Norton.