It's a common task for many of us who work in any form of IT position using Windows. Eventually you have to install/re-install a version of Windows and what follows is a very long OS updating process.

For a long time I have accepted the fact that this is a slow process and that's all there is to it. There is a lot to download, and some updates require restarts followed by further updates... Ugh!

This morning I had to go through the process of installing Windows XP with SP3. I'm installing the OS on a VM on an SSD and I've been working on this thing for over 6 hours.

Although, think there are many ways to knit-pick this process for improvements, there is one step that is always particularly slow and I can not figure out a good reason why.

That step is the detection step on a manual update. Specifically, when navigate to the Windows (or Microsoft) Updates page, and then click the 'Custom' button to detect your updates. It appears that your PC just sits there for a painful amount of time. Check your Task Manager and it looks like your PC is, in fact, locked because your CPU isn't cooking but that's certainly not the case. Somethings happening but I have no clue what's going on?

What is the updating software doing? If the registry was being searched, shouldn't my CPU usage peak?

Does anybody know what's happening? I can loosely justify why some of the steps in the update process take so long. However, this one doesn't seem to have any reasoning.