Spotlight-Search fails on (external) NTFS-Device (Harddisk), Mac spotlight index NTFS external drive

Go to Applications - Utilities - Terminal 

Type in:

/usr/bin/mdutil -i on /Volumes/NTFS_DRIVE
(Enter)
/usr/bin/mdimport /Volumes/NTFS_DRIVE
(Enter)

Where NTFS_DRIVE is the name of your NTFS external drive. Put quotes before and after the drive name if your drive name has spaces in it.