Hello, Maybe is an stupid question but, when I try to change some file in my nas200 (for example change the extension of a file mkv to avi) I recibe a message like this: You need permissions to do this action. Is necesary the permission of S-1-5-.......... to make changes in this file. If I try to chang a file to anothe folther I recibe a similar message and the computer say tha a mkv file is a system file Could somebody helpme. Sorry for my english. Thanks.