Default folder for backup files is C:\Users\[User name]\Titlevision\backup
Default folder for subtitle files is C:\Users\[User name]\Titlevision\subtitles unless "use last selected folder" is ticked.
Default folder for video files is C:\Users\[User name]\Titlevision\Videos. Change of video cache directory elsewhere (video/play or options/video configuration/video cache) will override this setting.