From: Chris McFarling on
How does Windows Update/Microsoft Update keep track of installed updates?
Does it check the filesystem for specific file versions or does it use a
database of some sort to determine what is and what is not installed?

From: LD55ZRA on
Chris McFarling wrote:

> How does Windows Update/Microsoft Update keep track of installed
> updates? Does it check the filesystem for specific file versions or
> does it use a database of some sort to determine what is and what is
> not installed?

It uses your registry entries. Windows registers everything in your
registry. YOU HAVE BEEN WARNED!