Autochk cannot repair system partition

Currently, the system boots, starts smss.exe and then autochk.exe so that any mounted volume at boot can be checked. If the system partition needs a check (and thus reparation), autochk will call the associated helper library.

With vfat, for example, that one will attempt to lock the FAT volume, repair it, and then, dismount it.

Unfortunately, this cannot work, because of open handles on the FS. One is notably due to autochk itself, and its working directory; a handle is stored in the PEB.