The Windows Defender program in Windows 8 and Windows 10 versions of Windows helps you protect your data from viruses, malware and various other threats. As you likely know, the Defender in Windows 10/8 is nothing but a cut-down version of Microsoft Security Essentials. With default settings, Windows Defender in Windows 10 and Windows 8.1 downloads and installs required updates once a day and doesn’t require manual intervention. That is, Defender automatically checks for update and downloads updates, if available. But if your PC isn’t connected to the internet or for some other reason you want to manually install updates, you can do so by following the given below instructions. This guide is based on our previously published how to manually download Microsoft Security Essentials update guide. Manually download and install Windows Defender updates in Windows 10/8.1 Step 1: Check the version (32 or 64-bit) of Windows 10/8.1 installed on your PC. To do so, you can open Computer Properties by right-clicking on the computer icon on the desktop and then clicking Properties. And if you can’t find Computer icon on the desktop, follow the instructions in our how to add Computer icon to desktop guide. Step 2: Next, visit the following links to download latest updates for Windows Defender. Updates for 32-bit (x86) Updates for 64-bit (x64) Be sure to download the right version of the update as updates released for 32-bit can’t be installed on 64-bit PC and vice versa. Step 3: Once the update file downloaded, navigate to the download folder containing the update and double-click on the same to install the same. That’s it! How to remove Scan with Windows Defender from context menu an how to disable Windows Defender permanently in Windows 10 guide might also interest you.