@Tong_Long ----- Thank you for your feedback and sorry for the inconvenience. I would like to gather some more information from you regarding your setup, so I can understand exactly what equipment you are working with.
Can you please, in detail, describe your current setup. The more detailed you are the easier it will be for us to start eliminating variables as a cause to this issue.
“Then I try to fix it. I mean to edit the music information (singer and album). And I can not edit it, May I ask How can I do this? Because I can easily do this in itunes.”
Currently in roon you can edit the display of the artist and album names but links to things like credits, album performers, and composers can not be edited. We plan on adding these functions in the future.
“The system just break when I tried to delete any song ! I am not sure what is wrong (maybe my system?) / So, How could I delete songs from Roon?”
What storage device are you using? What is happening when you try to delete content?