Footnote

The drive letter currently used to access this volume. May be different from Drive_Letter_Preference if there was a conflict (i.e. Drive_Letter_Preference is already in use by another volume).

Note: When the volume drive letter is changed using the Assign_Drive_Letter function, the Drive_Letter_Preference field reflects the requested change immediately; however, the Current_Drive_Letter field will contain a null character (0) until all changes are committed and the LVM engine is refreshed.

This is because a drive letter conflict could potentially occur up to the point hen the changes are committed. The null character serves as a flag for the application to indicate that the drive letter assignment is not yet fixed.