It's historical (backwards 'compatible'). In previous versions of Windows you could
check now. I'm not sure when it changed (XP, maybe Vista) but it's better to check the drive without anythng running - before Windows loads drivers and services that hit the disk.
Quote: Originally Posted by martinlest
.....just wanted to know how the MS window works. .....Why no way to 'Check Now'. Seems a pointless window.
The disk is normally checked after the next boot.