Download the Microsoft Security Essentials update files that are appropriate for your version of Windows. Unsure which version you have? Go to the next tab.
32-bit (x86-based) version
64-bit (x64-based) version
Follow these steps to determine your version of Windows:
Click "Start" or click "Start Search," then click "Run."
Type "msinfo32" in the Open box, then click "OK."
See "OS Name" to find your operating system.
See "System Type" to find your version of Windows.
To resolve an issue in which Microsoft Security Essentials does not update automatically, try these steps:
Reset your Internet Explorer settings. For details, seethese steps.
Set Internet Explorer as the default browser.
Ensure that the date and time are set correctly on your PC.
Rename the Software Distribution folder on your PC.
Reset the Microsoft antivirus update engine on your PC.
Article ID: 4026492 - Last Review: 01 Aug 2017 - Revision: 1