Microsoft Security Essentials Acting Strange

andreaerdna said:

I also have the same issue on Windows 7 Home 64bit...
...Does this mean I will always manually download the virus definition from now on?

I'm afraid so, that's what I do now.

andreaerdna said:

"I also have the same issue on Windows 7 Home 64bit...

...Does this mean I will always manually download the virus definition from now on?"


It's worth it. Same definitions as Windows 10/11, for free.

Thanks for the tip on how to manually update security essentials. I am still using a Windows 7 machine I built 14 years ago that I use as an HTPC with a cable card and (knock on wood) it still runs like a champ. Thanks again,

Hi All - I originally generated this post 2 weeks ago - I thought I had resolved this issue, yet here I am again back to square one wit the same issue everyone is having - I was away for a few days, and up[on my return, my MSE has not been updated since 2/27/25 - going on 8 days now - I took the advice of one fella, Unistalled MSE, and then went about installing it again, straight the designated Microsoft website page- HOWEVER, this time, after running the .exe file, it just disappears, nowhere to be found, not listed under installed programs, nothing!! WTF! Anyhow,l so as to have some type of defense, I re-activated Windows Defender - not thrilled with it, but better than nothing-
Can anyone please help me get MSE back on my machine: per other folks advice, I don't mind updating manually if that's what it takes, it's just that I trust MSE - please let em know your thoughts on this quagmire I/we are in - Thank you kindly!!

- - - Updated - - -

By way of update, I was able to get MSE re-installed, and it is currently running a quick scan -
As per other folks advice, I will manually update MSE - Normally, my machine informs me that there is an update available, usually everyday, then I grant permission to install it -
Now This may sound silly, yet how do I manually update MSE??- Please advise, thanks!

Followed your advice, and I am told my system is now protected and definitions are up to date!!

Thank you kind sir!

Had same issue here. When I ran the Update check, it just never came back with anything. I downloaded the update manually, ran it (odd there is no screen or any UI element telling you it is running) and a few moments later MSE turned green and I was updated

Is https://www.microsoft.com/en-us/wdsi/defenderupdates always the URL to check for MSE updates?

Willmarth said:

Use the following link and you'll find this list of exe files that contain updated definitions. Download and run. This worked for me on the 5th and when I checked on the 6th there were no new definitions: https://www.microsoft.com/en-us/wdsi/defenderupdates

Microsoft Defender Antivirus for Windows 11, Windows 10, Windows 8.1, and Windows Server	32-bit | 64-bit | ARM
Microsoft Security Essentials	32-bit | 64-bit
Windows Defender in Windows 7 and Windows Vista	32-bit | 64-bit
Microsoft Diagnostics and Recovery Toolset (DaRT)	32-bit | 64-bit
System Center 2012 Configuration Manager	32-bit | 64-bit
System Center 2012 Endpoint Protection	32-bit | 64-bit
Windows Intune	32-bit | 64-bit

I just tried again and updated with the March 6th definitions. It looks like I'll be downloading the Windows Security Essentials exe daily from now on until the automatic update feature begins working again (fingers crossed.)

Thank you very much for that. I downloaded Microsoft Security Essentials, 64 bit, ran it, and MSE updated.

Possible fix to restore MSE autoupdates - folks on Reddit are having luck with this solution using EasyFix (I haven't tried it yet):
(from https://www.reddit.com/r/windows7/co...nd_of_support/)

EasyFix download link:
https://download.microsoft.com/downl...syFix51044.msi

EasyFix really works ! After install I can check for new definitions in MSE itself again, after many years :-D !