You see on the Internet that companies selling this product usually sell genuine products. In fact, they usually sell serial numbers, and then ask you where to download installation files. Nothing special. If you buy this product from a company, find a company that sells this product. There are many online products, and generally there are no fakes (you can call solidworks China to ask if this company is their agent). Forget it if you buy it yourself. It will have the same effect next time.