I've got Windows/Microsoft Update on my Windows 7 laptop set to notify me when updates are available but not to do anything automatically.

I also have Windows Defender running and it seems to have daily or semi-daily updates for its signature database but it uses Windows Update utility to get and install these updates.

Is there a way to automatically download and install the Windows Defender signature updates but leave the rest of Windows Updates set to manual?

  • 2
    this has bothered me for so long. i never took the 2 minutes to google whether or not this was possible. now i know :)
    – kenwarner
    Jul 2, 2010 at 22:49
  • I personally set up a daily schedule to run a task. [Here's how][1]. [1]: superuser.com/a/742214/243263
    – MikeF
    Apr 15, 2014 at 23:44
  • I personally set up a simple daily task via the Task Scheduler. [Here's how.][1] [1]: superuser.com/a/742214/243263
    – MikeF
    Apr 15, 2014 at 23:45

2 Answers 2


The answer is yes.

With the Windows Update settings set to "Check for Updates but let me choose whether to download and install them", you may set the Windows Defender settings to check for new definitions before a "Windows Defender Scheduled Scan".

To automatically check for new definitions before Windows Defender scheduled scans (recommended):

  1. Click to open Windows Defender by going to Control Panel > Windows Defender

  2. Click Tools, and then click Options.

  3. Under Automatic scanning, make sure the "Automatically scan my computer (recommended)" check box is selected.

  4. Select the "Check for updated definitions before scanning" check box, and then click Save. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

Source: Microsoft Support

  • Does Windows Defender need to run as a per-user tray application for this to work? I have set this and Windows Update still continues to prompt me for "Definition Updates".
    – palswim
    Nov 5, 2010 at 16:53
  • 2
    Anyone know if this can be done in Windows 8? The options section have changed. Jun 11, 2012 at 9:41
  • 2
    @Lillemanden: see superuser.com/questions/499545/… i modified that answer to describe how you update the signatures before doing a scan.
    – akira
    Nov 21, 2012 at 17:25

I couldn't find this option on the version of Windows Defender bundled with Windows 8, but these commands in a .BAT file work for me:

pushd "C:\Program Files\Windows Defender"
MpCmdRun.exe -SignatureUpdate

I then created a scheduled task to run this at 4am every morning.

(The pushd/popd are so I can also run it from the command line on demand.)

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