: When you start Rhino for the first time after installation, you will see a dialog box that says “Rhinoceros 6 License Required” .
If you purchased a license, search your email inbox for the confirmation from McNeel. The email will contain your license key, which starts with "RH60"【0】【7】. Rhino 6 License Key Rh60 -2021-
If you need legitimately: