Hi Antonio and Carlos, Indeed, DPLUnlockKeyA works, thanks very much! nUnlock := DllCall( hDLL, DC_CALL_STD, "DPLUnlockKeyA", nInstanceID, cLicenseUSD ) -> this works nUnlock := DllCall( hDLL, DC_CALL_STD, "DPLUnlockKey", nInstanceID, AnsiToWide(cLicenseUSD) ) -> this does ...