Windows patch KB 3139929: When a security update is not a security update
Found on InfoWorld on Thursday, 10 March 2016
If Microsoft's documentation is correct, installing Patch Tuesday's KB 3139929 security update for Internet Explorer also installs a new Windows 10 ad-generating routine called KB 3146449.
It's important to note that KB 3146449 is not installed separately. You can't remove it. If you look in your installed updates list, KB 3146449 doesn't appear. Instead, it's baked into the IE security patch KB 3139929. The only way to get rid of the new advertising inside Internet Explorer 11 is to remove the security patch entirely.
Another reminder to keep automatic updates always disabled. It's a pain to see that you have to invest your time to keep adware, spam and nagware off a system when you just want to update it.