diff --git a/mcserver b/mcserver
index 0bb91fa..ebed416 100755
--- a/mcserver
+++ b/mcserver
@@ -16,6 +16,15 @@ _stop_and_wait () {
 	done
 }
 
+_start () {
+	! tmux $TMUX_OPTS has-session > /dev/null 2>&1 && \
+		tmux $TMUX_OPTS new-session -d -s $TMUX_SESSION "./start.sh" || \
+		die "Instance $instance is already running."
+}
+
+_send_command() {
+	tmux $TMUX_OPTS send-keys -t "$TMUX_SESSION" -l "$code_clear" "$*" "$code_send"
+}
 
 # directories
 mcserver_root="${XDG_DATA_HOME:-${HOME}/.local/share}/mcserver"
@@ -59,6 +68,6 @@ TMUX_OPTS="-L mcserver"
 
 case "$cmd" in
 	stop) _stop_and_wait ;;
-	command) tmux $TMUX_OPTS send-keys -t "$TMUX_SESSION" -l "$code_clear" "$*" "$code_send" ;;
-	start|*) tmux $TMUX_OPTS new-window -t $TMUX_SESSION: "./start.sh" || tmux new-session -d -s $TMUX_SESSION "./start.sh";;
+	command) _send_command ;;
+	start|*) _start ;;
 esac