Why does my machine take forever to shut down?

It's important to realize that shutting down the computer is almost as complex a process as starting it up it. Once you tell Windows that you want to shut down it in turn asks (yes, asks) each currently program if shutting down is OK. Then after each program has been asked then each program is then told that Windows is shutting down.

Why this seemingly complex chain of events? Naturally, it's a feature! If you have unsaved edits in your word processor then you want Windows to tell it so that it has a chance to save those edits or ask you what to do. Some applications need to be in a certain state before powering down, so they're given the opportunity to say "No!" to abort the shutdown.

So it's easy to see that shutdown speed is at the mercy of every peice of software you have running when you shut down. Each has to be asked and each has the opportunity to perform some work, perhaps even time consuming work, before Windows shuts down. In the worst case scenario they can pause the shutdown process completely as they ask you things like "do you want to save this file first?". As a result, I rarely "just" shutdown Windows. I close each application I'm running (or at least the "big" ones) first.

What about all that software that's running that you didn't start? Of particular note are the applications that started automatically; instant messaging applications, real-time virus checkers, and so on. They also have the opportunity to take time to clean up before shutting down. Check out this prior article, What's all this stuff running after I boot Windows? for help in identifying and possibly removing some of the items that slow down your startup as well as your shutdown.

Another common cause for shutdown slowdowns is the network. There are various types of network connections, from files being shared across a LAN, to instant messaging conversations in progress, with many more in between. Each connection needs to be individually closed on system shutdown. In many cases that means that whatever you're connected to needs to be informed that you're no longer connected. If the remote side is slow or non-responsive, that can contribute to how long Windows takes to close that connection on shutdown.

There are certainly hardware problems that can result in slowdowns on shutdown. More commonly there are conflicts or issues with the device drivers - the software used to control the hardware - that cause shutdown problems. Actual hardware issues more commonly cause problems at other times as well. Make sure your drivers are up to date. Conversely, if you start experiencing a problem after updating a device driver, then it'd make sense to check with the manufacturer.

Finally, there's the issue of viruses and spyware. They can certainly wreak havoc in many ways not limited to shutdown. Most cause problems at other times, but have been known to affect shutdown as well. Check out the prior article How do I keep my computer safe on the internet? for some tips on keeping them off your machine.

Typically each situation is a little different. These guidelines should allow you to narrow down the causes of your slowdown, and eventually, fix it.