One of the most common pitfalls for users is upgrading their hardware without their old setup first. Because the authorization code is "exclusive" to your specific hardware ID, simply uninstalling the software does not free up your license. VOCALOID6 Installation and Authorization (Windows)
Obtaining an authorization code for Vocaloid 6 is a straightforward process. Here's a step-by-step guide: vocaloid 6 authorization code exclusive