Windows registry keys associated with the MELSOFT license have been moved, deleted, or corrupted.
The most reliable fix is often to re-input your license key. You don't always need to uninstall the whole suite to do this: gt designer license not found
The Product ID was never entered during the initial installation of the GT Works3 suite. Windows registry keys associated with the MELSOFT license
Mitsubishi often includes a management tool within the installation folder. gt designer license not found
Before diving into technical fixes, try right-clicking the GT Designer icon and selecting Windows occasionally blocks software from reading license data stored in protected system folders. If this works, you can set it to always run as admin via the Compatibility tab in "Properties." 2. Re-register the Product ID