I have a PlexPass and everytime that I go to download a new version of Plex Media Player, Windows Defender SmartScreen attempts to block the download. I have to go through extra steps to save the download. I have already reported to Microsoft that this program is safe, but it does not seem to help. According to what I’ve read, the publisher (Plex, Inc.) can also request that their software is white listed.
Instructions from Microsoft for submissions…
You can immediately submit a request for a correction. Windows Defender SmartScreen has a built-in, web-based feedback system in place to help customers and website owners report any potential false warnings as quickly as possible. In Windows Internet Explorer, from a red warning, click More information then Report that this site contains no threats. This will take you to a feedback page where you can indicate you are a site owner or representative. Follow the instructions and provide the information on this site to submit a site for review.