In the rare instances that I must use IE, I rely on Adblock Plus.
I too can no longer see the icon in the taskbar.
I reset IE, I rebooted, but prior to that, I reinstalled ABP.
It is enabled and I assume it's working, but there is nothing like the assurance of seeing the red icon in the lower right corner. (I don't search with IE, I have to open a specific website, usually a state site.)
Since I had to uninstall it first, I know it was installed and likely working.
To tell you the truth, when Win10 does its monthly updates, it knocks off or out some key feature(s). I would blame Win10 before I blame any other add-on, extension, or valued software.
Fortunately, it works great on Firefox, my forever default browser, but like I said, when I MUST use IE11, I like to see it.
Please let me know if you find a fix.
Thank you.