Change Microsoft Security Essentials’ Update Frequency

Change Microsoft Security Essentials’ Update Frequency

Microsoft Security Essentials is still our favourite antivirus tool, but its update method can cause some problems. Here’s how to change the update interval with a registry hack.

If you keep your computer on all day, MSE should update just fine once every 24 hours, which is certainly enough for the average user. However, if you’re using it on a laptop, you might miss out on updates because you’re constantly sleeping, resuming or not connected to Wi-Fi at any given time. If you find that you have to constantly update manually to get the latest virus definitions, you may be better off tweaking this registry key to make it check for updates more often, thus increasing the chances it checks while it’s on and connected to the internet.

Open up the Registry Editor in Windows and head to HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Microsoft Antimalware/Signature Updates. Right click on Signature Updates, hit Permissions, then hit Advanced. Head to the Owner tab, click on the Administrators group and hit OK. Then, back at the Permissions window, check the box labelled “Full Control” while the Administrator’s group is selected.

Next, double click on the SignatureUpdateInterval key, and change the number from something between 1 and 24. This will be the number of hours it waits to check for a new update (the default being 24). Once you’ve done so, you can change the permissions back (where SYSTEM owns the key and Administrators do not have full control). If all goes well, you should notice MSE is a bit better about staying updated from now on. Thanks Frank!


  • What I want to know is if you disable automatic updates in Windows, it seems to stop MSE from auto updating. It just means I need to manually install the updates each time.

    Is there some way that I can make MSE the exception and it auto update, but Windows doesn’t?

    (I use Win7)

    • To ensure that my laptop, which is used less frequently than my desktop pc, has the latest MSE AV definitions, I just did a short cut of the update command and placed in the Start Up folder. The properties section should look something like this:
      “C:Program Files/Microsoft Security Client/Antimalware/MpCmdRun.exe” -SignatureUpdate.
      Under Run I minimised the window.
      So now on every boot up it checks and installs the latest signatures.

  • @Justin: you can update MSE by putting the following command in Scheduled Tasks:

    “C:\Program Files\Microsoft Security Essentials\MpCmdRun.exe” -SignatureUpdate

    Change the path if the program is installed elsewhere on your system.

    • Pete,

      The quotes in your post were smart quotes. I’m re-posting with real quotes – which will either work, or prove that the lifehacker website is converting them to smart quotes.

      “C:\Program Files\Microsoft Security Essentials\MpCmdRun.exe” -SignatureUpdate

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