diff --git a/src/freedombone-app-tox b/src/freedombone-app-tox
index 36bd0a94..11cc7c4f 100755
--- a/src/freedombone-app-tox
+++ b/src/freedombone-app-tox
@@ -189,8 +189,10 @@ function remove_tox {
 }
 
 function configure_firewall_for_tox {
-	if grep -Fxq "configure_firewall_for_tox" $COMPLETION_FILE; then
-		return
+	if [ -f $COMPLETION_FILE ]; then
+		if grep -Fxq "configure_firewall_for_tox" $COMPLETION_FILE; then
+			return
+		fi
 	fi
 	if [[ $INSTALLED_WITHIN_DOCKER == "yes" ]]; then
 		# docker does its own firewalling
@@ -204,7 +206,9 @@ function configure_firewall_for_tox {
 	save_firewall_settings
 
 	OPEN_PORTS+=("Tox      $TOX_PORT")
-	echo 'configure_firewall_for_tox' >> $COMPLETION_FILE
+	if [ -f $COMPLETION_FILE ]; then
+		echo 'configure_firewall_for_tox' >> $COMPLETION_FILE
+	fi
 }
 
 function tox_avahi {