Q. I have both "Megurine Luka V4X" and "VOCALOID4 Editor for Cubase" installed on my computer. However, "Megurine Luka V4X" does not appear in the window to select singers, and therefore I cannot use the Voice Bank.
Update your VOCALOID4 Editor for Cubase to the latest version.
The updater for the latest version is available at: Download
(* "Megurine Luka" is a registered trademark of Crypton Future Media, Inc.)