Sorry to reopen this thread but I'm having this same issue. I have already checked the file permission and it's everything ok but the system continues to warning me that there is no application installed for "shared library" files and asking me if want to search one. I try to execute the app through the terminal and I got the message: "The program 'nw' is currently not installed. You can install it by typing sudo apt install newtrw. So, I did it and now, when I try to open the nw in the terminal, it shows a lot of options (nw [udp] <options> <host> <port>) . In the file manager, all remains the same (Could not display 'nw'. There is no application installed ...). I really need to show this demonstration for a possible client that only use linux. Any help, please?