NavSync is automatically disabled when Navbox is activated for a user.
If it's the main NavStick you're trying to update with NavSync, please insert the NavStick in computer with NavBox software/Navbox hw to get it updated.
If it's the backup NavStick you're trying to update with NavSync, please note that the NavBox is the primary back-up for the main-NavStick, and vice-versa. If needing the back-up NavStick in the future, we can easily enable the back-up NavStick to be used with NavBox, and then update it from the NavBox.
Please keep the back-up NavStick in a safe place until needed, and then send us an email and we will change accordingly in our system.