Mozilla ActiveX Plug-in has been blocked for your protection.

Why was it blocked?
This plugin was discontinued years ago and only worked up to Firefox version 1.5. Because plugins aren't marked as incompatible, there are still many users who have it installed and have recently been experiencing crashes related to it.
Who is affected?
All Firefox users who have this plugin installed.
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.