I had an update on my work laptop in a partially installed state. Our vulnerability scanner determined one file, MSO.dll, was still out of date. It recommended a patch to apply. Running it gave me an error message. Here’s what to do when Windows says the update is already installed on this system and refuses to let you do anything but click OK.
Because hey, from a security analyst’s point of view, this is anything but OK. I get questions about patches in a partially deployed state all the time, so I figured I’d write about it. Here’s what I do when security updates fail to apply with this error.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.