This is pretty stupid to tie in updates for the OS to the updates for the security software (when the former happens once a month and the latter one -- once a day.) But, we're dealing with Microsoft ...
I couldn't seem to find an easy way to make Windows Defender auto-update itself on my Windows 8.1, so I came up with this solution:
Go to Control Panel -> (Switch to classic view) -> Administrative Tools -> Task Scheduler.
Set up a recurring daily task to run the following command (with double-quotes):
"C:\Program Files\Windows Defender\MpCmdRun.exe"
with the following arguments:
-SignatureUpdate
I personally set it to run at 9 AM daily, but you can pick your own time.
PS. I know, Microsoft Task Scheduler is an obtuse creature
that needs a long tutorial of its own, but the good thing is that you have to deal with it only once.
1If you don't like auto-updates, and you think Defender is waiting for you to OK the updates, then what "Fix" are you looking for? – Ƭᴇcʜιᴇ007 – 2012-11-04T17:52:36.543
2@techie007 I don't like software auto-updates because I don't like the system suddenly saying I have to reboot. Updating malware signature files is another matter. – Isaac Rabinovitch – 2012-11-04T18:01:29.170
@IsaacRabinovitch So you're suggesting that you (and the OP as well?) want Defender to update automatically, but not Windows Updates? – Ƭᴇcʜιᴇ007 – 2012-11-04T18:05:53.497
I'd like to have the virus signatures have the autoupdate, but having a manual control on the system updates – Magnetic_dud – 2012-11-04T18:40:23.977