Microsoft has posted a long and complex explanation to its Windows Software Update Services (WSUS) blog, explaining the latest case of why software updates are being pushed to users who believe they’ve turned automatic updating off.

The UK Register reported on October 25 that a number of admins were seeing Microsoft Desktop Search 3.01 pushed out to users via Microsoft’s WSUS enterprise patching/update system, in spite of having opted out of this “resource-hogging search app.”

Bobbie Harder, Microsoft Product Manager for WSUS, explained why some companies were seeing the updated Windows Desktop Search bits (aka, the updated package for KB917013) pushed to their users. It turns out Microsoft changed the deployment rules after the original release of Windows Desktop Search. Harder noted:

“The original update release, released February 2007 as an optional update, was only applicable on systems which had a version of Windows Desktop Search installed. The recent update Revision 105, had the applicability logic expanded to be applicable to all systems regardless if a prior version of Windows Desktop Search was installed, IF of course, approved in the WSUS Administrative UI or via Administrator-set auto-approval rules.”