Download Uninstaller from here:
http://info.kmtronic.com/software/ftdi/CDMUninstaller_v1.4.zip

Disconnect all FTDI devices from PC !!!

Run "CDMuninstallerGUI.exe"

Click on "Add" button

Click on "Remove devices" button

Connect again device to PC and install drivers

http://info.kmtronic.com/ftdi-virtual-com-port-drivers-installation.html