I came here to troubleshoot the very same issue. Resilio Sync Home Pro pops up at startup on all my devices, stealing focus from other applications, despite the /MINIMIZED flag being present in the registry. I know this seems a minor annoyance, easy fixable with one mouse click, but this also happens on my media center pc, which I control only with a TV remote. All my devices run Windows 10 Pro, all patched to Version 1709, OS Build 16299.125. This happens on fresh install as well.