With the current reputation of Microsoft, people started checking what updates do. Checking what files were affected, what was installed and how the system changed. This made Microsoft worry they won't be able to push spyware via Windows Update.

The solution? Encrypted updates. A new method of delivering updates that completely hides the files installed, their purpose, and maybe even unlists them from "Installed Programs"? It would only make sense, given how people over-analyze their updates.