Define o atributo "archive" na pasta.
On Windows and OS/2, when a file is created or modified, the archive bit is set, and when the file has been backed up, the archive bit is cleared. It is by use of the archive bit that incremental backups are implemented.
Você pode ver se o atributo de arquivamento está definido na linha de comando com attrib [file]
(um A estará presente se estiver definido) e definir ou removê-lo com attrib +A [file/folder]
ou attrib -A [file/folder]
.