O modo de força bruta é:
ps waux | grep screen
Encontre o pid e faça um kill -9
nele ...
Caso contrário, experimente esses argumentos de linha de comando na tela :
-D [pid.sessionname] Do not start screen, but instead detach a screen session running elsewhere (see section 8.1 Detach). '-d' has the same effect as typing C-a d from the controlling terminal for the session. '-D' is the equivalent to the power detach key. If no session can be detached, this option is ignored. In combination with the -r/-R option more powerful effects can be achieved:
-d -r
Reattach a session and if necessary detach it first.
-d -R
Reattach a session and if necessary detach or even create it first.
-d -RR
Reattach a session and if necessary detach or create it. Use the first session if more than one session is available.
-D -r
Reattach a session. If necessary detach and logout remotely first.
-D -R
Attach here and now. In detail this means: If a session is running, then reattach. If necessary detach and logout remotely first. If it was not running create it and notify the user. This is the author's favorite.
-D -RR
Attach here and now. Whatever that means, just do it.
Note: It is a good idea to check the status of your sessions with screen -list before using this option.