I'm honestly completely confused now. I installed some back updates and rebooted and it's working again. I was mistaken, I didn't have MS Defender working. It was Security Essentials and it seemed to be broken when I was testing. It's working now.
After it stopped, it never "failed", it was impossible to refresh and load new pages. When I restarted the browser it would ask if I wanted to finish the downloads that didn't finish before I closed the browser last time. If I click yes it would lock up again and do nothing.
Regardless this is a bug that needs to be fixed because it doesn't matter if the download finishes, the browser shouldn't stop working completely.