msu installer) is that KB4474419 is already installed on your desktop computer. According to the MS support article for KB4474419 there are no prerequisites for this update, and as far as I know KB4474419 has not been superseded (replaced) by a newer update, so I would agree with PKCano the most likely reason for that error on your computer (assuming you are certain you have a 64-bit OS and downloaded the correct 64-bit. The MS support article Windows Update Troubleshooting lists some of the common causes of this “ The update is not applicable to your computer” error. I use Webroot Internet Security, but since I successfully downloaded the file, I can’t see where disabling it would make any difference to the installation. I think I would rather continue to dismiss the warning on Firefox than start editing the registry. Searches present a variety of solutions, not all of which apply. If anyone else has run into this problem, I would appreciate their input. I checked for installed updates in case it was already installed, but it was not in the list. It was set to Manual start, so I set it to Automatic start, but I’m not sure if that would make any difference in a stand-alone installation. I checked my Services and saw that while the Windows Update Service was running. I double-checked that I had the correct file downloaded, and I do. I got a pop-up saying, “The update is not applicable to your computer.” I downloaded the appropriate file from the Microsoft catalog, created a backup and a system restore point, and tried to install the patch. I did a test run on my Windows 7 laptop last week with no issues, so I decided to update my desktop machine.

I knew I needed KB4474419, but wanted to be sure it wouldn’t mess up a system that was already working. Firefox is my preferred browser, and I finally got tired of dismissing the message about an available update that appeared when Firefox 100 came out.

Kb4474419 and kb4490628