Here's a little interesting "data leak" I noticed. I double-clicked on an mp3 file and it loaded "Groove Music" (the new music player). Groove Music immediately began scanning my disk for music and uploading something. I stopped Groove, changed the configuration of Groove to not scan for music. I also created an empty folder and redirected Groove to only look for music in that folder. Groove nonetheless wants to scans my entire drive for music no matter the privacy settings.
Fortunately the old music player is still in Windows 10, even though its not the default. VLC works fine, too.
Microsoft really does strip mine our PCs in return for the "free" Windows 10. The lawyers should have a field day with this soon.