Windows Defender Offline beta lets you scan Windows before startup
Microsoft has rolled out the latest build of the Windows Defender Offline beta, a version of Windows' anti-spyware feature that is meant to be executed from a DVD or USB flash drive before Windows even starts up.
Windows Defender is included with Windows and has agents that can be run periodically, or at all times on a running system. Because it runs inside Windows, though, it is limited in what it can do.
This is what Windows Defender Offline is supposed to fix. It has been designed to scan your system for more elusive malware such as rootkits, or viruses that aren't constantly running processes and only act at startup or at unpredictable times. To do this, it needs to be installed on a piece of removable media so the user's Windows system can then be booted after Windows Defender Offline runs.
Windows Defender Offline interrupts the typical Windows startup process with the familiar Windows Defender interface. From there, users can opt to perform quick, full, or custom scans of the Windows system before it begins running. Give it a try!