diff --git a/fhem/FHEM/74_Unifi.pm b/fhem/FHEM/74_Unifi.pm
index cb598fe84..ff2a2c232 100644
--- a/fhem/FHEM/74_Unifi.pm
+++ b/fhem/FHEM/74_Unifi.pm
@@ -838,8 +838,8 @@ sub Unifi_SetHealthReadings($) {
     readingsBulkUpdate($hash,'#UC_wlan_users',$hash->{wlan_health}->{num_user});
     readingsBulkUpdate($hash,'#UC_wlan_accesspoints',$hash->{wlan_health}->{num_ap});
     readingsBulkUpdate($hash,'#UC_wlan_guests',$hash->{wlan_health}->{num_guest});
-    readingsBulkUpdate($hash,'#UC_unarchived_alerts',scalar @{$hash->{alerts_unarchived}});
-    readingsBulkUpdate($hash,'#UC_events',scalar(@{$hash->{events}}).' (last '.$hash->{unifi}->{eventPeriod}.'h)');
+    readingsBulkUpdate($hash,'#UC_unarchived_alerts',scalar @{$hash->{alerts_unarchived}}) if(defined $hash->{alerts_unarchived});
+    readingsBulkUpdate($hash,'#UC_events',scalar(@{$hash->{events}}).' (last '.$hash->{unifi}->{eventPeriod}.'h)') if(defined $hash->{events});
     
     return undef;
 }