Strangely this update is NOT automatically downloaded and run by Windows Update. Rather you have to manually download it from
Microsoft Update Catalog
Then run it. However, it runs silently, providing no positive indication or indication of any kind that it ran or didn't run or that it succeeded or failed... Absolutely nothing.
I had seen comments to this effect so I originally opted to do the manual steps described is this article.
https://support.microsoft.com/en-us...ive-execution-side-channel-vulnerabilities-in
TL;DR
The simpler solution is to use the
InSpectre utility from Gibson Research. Download and run that then click the button to disable spectre protection if necessary. This utility will indicate the status of protections for Meltdown and Spectre and it toggles the buttons to enable or disable the protection depending on the current state.