Running latest NAV on WIn7 Home Premium X64 (up-to-date) and NTFS dirty bit gets set at start-up. Re-boot into repair and reset using chkdsk /f (which reports no problems with drive) and verifying with chkntfs, Then reboot and chkntfs reports its dirty again but chkdsk finds no problems. Remove NAV and problem goes away,
Workaround is Chkntfs /x c: but that's not a good solution.
Help.