Easiest if you just see the pic. See mIRC, then see the two blue underlines next to it? those are the 2 ghost mIRCs. Ignore the fact I have facebook open in the back laugh
This pic is what it looks like when I right click the ghost to the immediate left of the main mirc window.
[Linked Image from i.imgur.com]

Two weird ghost mIRCs appear next to the main one in my Windows taskbar. I thought it might be related to multiple servers, but I disconnected from some until there was only one and they remained.

I can right click the ghost and choose "Close window" and it will destroy the ghost and have no effect on my channels or servers.

This is v7.66 on win 10 pro latest.