Make sure you download the most recent installer available to ensure you'll have the shortest amount of patches to download. An older installer file will prompt you to download more patch updates.
Restart your computer and internet connection.
If you're not receiving a Runtime error along with it freezing midway, make sure your internet connection is stable. If your internet connection goes in and out, it can make the patcher freeze .
Other than that, you'll need to try to force quit and restart the patcher until all of the patches download. It'll take a few tries until it downloads completely.