Start the VOCALOID4 Editor installer, and in the "Program Maintenance" dialog box, select "Repair".

If this does not resolve the problem, try the following.


1) If you are using Windows 7 and Service Pack 1 is not installed:

Go to either of the following websites:

http://www.microsoft.com/ja-jp/download/details.aspx?id=5842 (Japanese)
http://www.microsoft.com/en-us/download/details.aspx?id=5842 (English)

Depending on your OS environment, download and install one of the following:
windows6.1-KB976932-X64.exe (for 64-bit OS)
windows6.1-KB976932-X86.exe (for 32-bit OS) (If it has already been installed, skip this step.)


2) Use Windows Update to apply the latest patches.

3) Go to either of the following websites:

http://www.microsoft.com/ja-jp/download/details.aspx?id=30679 (Japanese)
http://www.microsoft.com/en-us/download/details.aspx?id=30679 (English)

Then, download and, install either of the following files using user authority:

VSU4/vcredist_x86.exe (for 32-bit VOCALOID4 Editor for Cubase users)
VSU4/vcredist_x64.exe (for 64-bit VOCALOID4 Editor for Cubase users)


4) Restart your computer, and activate Cubase.


5) In Cubase, under the "Devices" menu, select "Plug-in Information", and then in the "Program Plug-ins" tab, check whether the "VOCALOID4 Editor" check box is selected. If it isn't selected, select it.