When you install MSE it requires updating antivirus definition updates. This can create issue sometimes as the updates are quite big or when you are not connected to Internet. So, I’ve found update files which can let you update Microsoft Security Essentials offline.
Download the latest virus and spyware definition update files below:
- Download file for a 32-bit (x86-based) version of Windows
- Download file for a 64-bit version of Windows
These update files are executable files which can be installed easily without any issues.
Source: Windows Valley