This just started recently happening. I am using the Mezzmo client on Roku, but I doubt that is the cause.

When I stream a movie using Mezzmo, I can't move it to a new location until after I restart the Media Server service. It says that the file is open in ffmpeg.exe and won't let me do anything with it. I've already checked and the file isn't being transcoded. It doesn't even work once I start viewing a different movie.