I downloaded and installed the x64 on a USB drive and scanned. Worked out fine.
Although even though it says it just needs 250MB worth of space on a USB drive (which kind of implies it doesn't need to format it), it still needed to format the USB drive even though the drive was already bootable. So that was a little misleading.
And I specified what Drive to scan when I booted into the program when it asked, but it still scanned all my drives.
Guess one needs to still go into the Tools/Options of it and exclude what drives you don't want scanned.
Looks and acts just like Windows Defender. Even says "Windows Defender" when it boots up.