This error message indicates that the ARIA Player installed correctly but the Garritan library did not. To resolve this issue, please reinstall only the library (you can customize the installation by unchecking the ARIA Player when reinstalling). After installation, place the keycard on the ARIA Player again to activate the library.
Steinberg released Dorico Pro 6 on April 30, 2025.
If you have crossgraded from Finale to Dorico, please see this article for more information.