A recent Windows Update package, marked "Important", quietly added Microsoft's "Search Helper" extension to both Internet Explorer and Firefox, all for the purpose of making a Bing toolbar work better. Here's how to remove it.
Image via Ars Technica.
As Ars Technica explains, Microsoft pushed out an Important-labelled update for its "Search Enhancement Pack". Many Windows users always install the Important updates, as they're where security issues are regularly fixed. What the "enhancement" really did, though, was install a package that helps Bing's toolbar better integrate itself with IE and Firefox — whether or not you have the Bing bar installed. You'll notice it because Firefox will report having a new add-on when you next start it after the update.
You're probably fine leaving the helper installed for Internet Explorer, but if you don't like the extension cluttering up your Firefox, you can delete the "firefoxextension" folder from C:Program FilesMicrosoftSearch Enhancement PackSearch Helper. You may need Administrator rights to remove the file, but once you do, the extension should be gone from your Firefox install, according to vigilant mozillaZine Forums users. The SEPsearchhelperie.dll file is the IE add-on, in case you wanted to kill that off, too. Thanks to Stephen.Lecheler for the tip!
Microsoft hides mystery Firefox extension in toolbar update [Ars Technica]
Search Helper Extension (Removal) [mozillaZine Forums]