Windows Management Instrumentation (WMI) high CPU usage and a quick fix

I just got myself a fresh install of Windows 8.1 Pro. So imagine how annoyed I was to find out that the boot time was significantly longer than my old Windows XP. More importantly, one service seems to be hogging the CPU all the time – Windows Management Instrumentation.

Okay, to be fair, the average consumption was only 10 – 15%, but it was consistent and did not seem to go away even after several minutes post start-up. Again, to be fair, I did install some updates and stuff; the original factory set had no problems. Here’s a list of key things that I did before noticing the persistent CPU usage:

1. Set up an internet connection using Vodafone Mobile Connect (I hate having to install this buggy software which seems no longer supported in order to use the modem, but then hey that’s the best telecom subscription in my case).
2. Installed FastAccess via Dell Digital Delivery.
3. Launched Windows Update to get several of the latest updates.
4. Downloaded the Windows 8.1 Update 1 standalone installer from an external source with better internet connection, and installed it one by one.

Perhaps 10 – 15% is not a significant amount of CPU usage, and tech support may dismiss it as no cause for concern. But I believe when the CPU is supposed idle, then it should be idle; it makes no sense for the CPU to be running unless it is doing useful work. And how can a Windows process be doing more work than third-party antivirus software? Who is the culprit? With this in mind, I set out to fix this annoyance.

With some experience dealing with misbehaving servers at work, my first instinct was to restart the service. And voila! The high CPU usage was gone. There doesn’t seem to be any adverse impact. But on subsequent reboots, it came back. Checking the list of dependents on the service, I noted:

1. Intel® Rapid Storage Technology
2. Internet Connection Sharing (ICS) (which was disabled anyway)
3. IP Helper
4. Security Center
5. Vodafone Mobile Connect Service

Perhaps a reasonable test would be to disable the services one by one to find who the culprit is, so I tried that. To my surprise, WMI still uses CPU even after all of them are disabled. I am not an expert of Windows architecture, my guess would be that WMI needs to do some background work whenever it’s started up as a preparation for the registered dependents, even when the dependents are disabled. Disabling WMI itself is certainly out of the question (VMC needs it so that I can connect to the internet).

Next I spent on Google Bing seeing if others are experiencing the same thing. It seems my situation is not unique. WMI doesn’t seem to have a good reputation. After some more hours and several restarts, I realized Security Center does not seem to detect McAfee properly – it reports the status as off, even though it is running. It reports the status, however, after WMI was restarted. Event Viewer seems to confirm this with errors coming from not being able to find the McAfee package (taking a screenshot was not on my mind at the moment).

I usually don’t use antivirus packages, and I think they are a waste of resources anyway. Firewalls are more important. All those virus definitions, for instance, is really nothing but a waste of my data plan. This one came pre-installed as it was bundled in the package. After confirming that I can indeed re-download using the existing subscription (who knows I may have a change of heart), I uninstalled it and rebooted. WMI CPU usage was cut down by half. Clearly, something wasn’t right with Security Center, WMI, and McAfee.

So, five more percent to go. I reckoned FastAccess isn’t useful to me as well, so proceeded to uninstall it. I installed it in the first place because it was included in the price, and I can re-download it later anyway. Indeed, these bundles make you pay for things you don’t need, but on the larger picture at least the price is still reasonable.

By luck, that did the trick. Now WMI is no longer at the top of the list.

Some readers are asking, I got this far with your babble, now where is the quick fix? Uninstalling packages is by no means a quick fix.

Here it is. First check what other services uses WMI. You can use services.msc to do this, and viewing the dependencies tab. Go to task scheduler and create a new task which launches at any user login, preferably with 1 or 2 minutes delay to make sure WMI and all other services have started:

net stop “Name of dependent service 1”
net stop “Name of dependent service 2”
net stop “Name of dependent service 3”
…
net stop Winmgmt
net start Winmgmt
net stop “Name of dependent service 1”
net stop “Name of dependent service 2”
net stop “Name of dependent service 3”
...

Basically what this does is to restart WMI and all other dependent services. The downside of this is of course a longer time until your machine is ready for use, and a bunch of cmd popups when the task is executed.

That’s all!

P.S. I also uninstalled the Synaptics touchpad driver, it uses CPU whenever I move the mouse cursor. I suppose the fancy finger gestures don’t justify that me, I don’t use them anyway. Now the CPU is really idling when it should be idle. And this new keyboard is simply comfortable to type on!