diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index d4a3436a..e414b871 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -899,12 +899,16 @@ class kolab_driver extends calendar_driver
     else if ($old['recurrence']['EXCEPTIONS'])
       $event['recurrence']['EXCEPTIONS'] = $old['recurrence']['EXCEPTIONS'];
 
+    // remove some internal properties which should not be saved
+    unset($event['_savemode'], $event['_fromcalendar'], $event['_identity'], $event['_owner'],
+        $event['_notify'], $event['_method'], $event['_sender'], $event['_sender_utf'], $event['_size']);
+
     switch ($savemode) {
       case 'new':
         // save submitted data as new (non-recurring) event
         $event['recurrence'] = array();
         $event['uid'] = $this->cal->generate_uid();
-        unset($event['recurrence_id'], $event['id'], $event['_savemode'], $event['_fromcalendar'], $event['_identity'], $event['_notify']);
+        unset($event['recurrence_id'], $event['_instance'], $event['id']);
 
         // copy attachment data to new event
         foreach ((array)$event['attachments'] as $idx => $attachment) {
@@ -921,16 +925,13 @@ class kolab_driver extends calendar_driver
         // recurring instances shall not store recurrence rules and attachments
         $event['recurrence'] = array();
         $event['thisandfuture'] = $savemode == 'future';
-        unset($event['attachments']);
+        unset($event['attachments'], $event['id']);
 
         // increment sequence of this instance if scheduling is affected
         if ($reschedule) {
           $event['sequence'] = max($old['sequence'], $master['sequence']) + 1;
         }
 
-        // remove some internal properties which should not be saved
-        unset($event['id'], $event['_savemode'], $event['_fromcalendar'], $event['_identity'], $event['_notify']);
-
         // save properties to a recurrence exception instance
         if ($old['recurrence_id'] && is_array($master['recurrence']['EXCEPTIONS'])) {
           foreach ($master['recurrence']['EXCEPTIONS'] as $i => $exception) {
diff --git a/plugins/libcalendaring/libcalendaring.php b/plugins/libcalendaring/libcalendaring.php
index c3bf6256..63a05488 100644
--- a/plugins/libcalendaring/libcalendaring.php
+++ b/plugins/libcalendaring/libcalendaring.php
@@ -1414,7 +1414,7 @@ class libcalendaring extends rcube_plugin
         if (!empty($object['recurrence_date']) && is_a($object['recurrence_date'], 'DateTime')) {
             $recurrence_id_format = $object['allday'] ? 'Ymd' : 'Ymd\THis';
             $object['_instance'] = $object['recurrence_date']->format($recurrence_id_format);
-            $object['_savemode'] = $event['thisandfuture'] ? 'future' : 'current';
+            $object['_savemode'] = $object['thisandfuture'] ? 'future' : 'current';
         }
         else if (!empty($object['recurrence_id']) || !empty($object['_instance'])) {
             if (strlen($object['_instance']) > 4) {
diff --git a/plugins/libkolab/lib/kolab_format_event.php b/plugins/libkolab/lib/kolab_format_event.php
index fe10f9d6..a5b0f737 100644
--- a/plugins/libkolab/lib/kolab_format_event.php
+++ b/plugins/libkolab/lib/kolab_format_event.php
@@ -103,7 +103,6 @@ class kolab_format_event extends kolab_format_xcal
             foreach((array)$object['recurrence']['EXCEPTIONS'] as $i => $exception) {
                 $exevent = new kolab_format_event;
                 $exevent->set(($compacted = $this->compact_exception($exception, $object)));  // only save differing values
-                console('COMPACTED', $compacted);
 
                 // get value for recurrence-id
                 if (!empty($exception['recurrence_date']) && is_a($exception['recurrence_date'], 'DateTime')) {