diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index dcd4c98b..ce194ff8 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -3464,7 +3464,7 @@ $("#rcmfd_new_category").keypress(function(event) {
                             $update_attendees[]   = $attendee;
                             $metadata['fallback'] = $attendee['status'];
                             $metadata['attendee'] = $attendee['email'];
-                            $metadata['rsvp']     = !empty($attendee['rsvp']) || $attendee['role'] != 'NON-PARTICIPANT';
+                            $metadata['rsvp']     = !empty($attendee['rsvp']) || empty($attendee['role']) || $attendee['role'] != 'NON-PARTICIPANT';
 
                             $existing_attendee_emails = [];
 
diff --git a/plugins/calendar/drivers/caldav/caldav_calendar.php b/plugins/calendar/drivers/caldav/caldav_calendar.php
index 260ca9cc..ec020b0e 100644
--- a/plugins/calendar/drivers/caldav/caldav_calendar.php
+++ b/plugins/calendar/drivers/caldav/caldav_calendar.php
@@ -64,14 +64,17 @@ class caldav_calendar extends kolab_storage_dav_folder
             // $this->storage = kolab_storage_dav::get_folder($folder_or_id, 'event');
         }
 
-        $this->cal        = $calendar;
-        $this->id         = $this->storage->id;
-        $this->attributes = $this->storage->attributes;
-        $this->ready      = true;
-        $this->alarms     = !isset($this->storage->attributes['alarms']) || $this->storage->attributes['alarms'];
+        $this->cal   = $calendar;
+        $this->ready = !empty($this->storage);
 
         // Set writeable and alarms flags according to folder permissions
         if ($this->ready) {
+            $this->id         = $this->storage->id;
+            $this->attributes = $this->storage->attributes;
+            $this->default    = $this->storage->default;
+            $this->subtype    = $this->storage->subtype;
+            $this->alarms     = !isset($this->attributes['alarms']) || $this->attributes['alarms'];
+
             if ($this->storage->get_namespace() == 'personal') {
                 $this->editable = true;
                 $this->rights = 'lrswikxteav';
@@ -86,9 +89,6 @@ class caldav_calendar extends kolab_storage_dav_folder
                 }
             }
         }
-
-        $this->default = $this->storage->default;
-        $this->subtype = $this->storage->subtype;
     }
 
     /**
diff --git a/plugins/kolab_addressbook/drivers/carddav/carddav_contacts_driver.php b/plugins/kolab_addressbook/drivers/carddav/carddav_contacts_driver.php
index 006a54e2..a7cec89a 100644
--- a/plugins/kolab_addressbook/drivers/carddav/carddav_contacts_driver.php
+++ b/plugins/kolab_addressbook/drivers/carddav/carddav_contacts_driver.php
@@ -162,8 +162,8 @@ class carddav_contacts_driver
         $result = $storage->folder_update($prop);
 
         if ($result && ($abook = $this->get_address_book($prop['id'] ?: $result))) {
-            $abook->id = $prop['id'] ?: $result;
-            $props = $this->abook_prop($abook->id, $abook);
+            $abook_id = $prop['id'] ?: $result;
+            $props = $this->abook_prop($abook_id, $abook);
 
             $this->rc->output->show_message('kolab_addressbook.book'.$type.'d', 'confirmation');
             $this->rc->output->command('book_update', $props, $prop['id']);