diff --git a/plugins/libkolab/lib/kolab_format.php b/plugins/libkolab/lib/kolab_format.php
index c54558eb..a4147812 100644
--- a/plugins/libkolab/lib/kolab_format.php
+++ b/plugins/libkolab/lib/kolab_format.php
@@ -265,7 +265,7 @@ abstract class kolab_format
     {
         // get generated UID
         if (!$this->data['uid']) {
-            $this->data['uid'] = kolabformat::getSerializedUID();
+            $this->data['uid'] = $this->xmlobject ? $this->xmlobject->getSerializedUID() : kolabformat::getSerializedUID();
             $this->obj->setUid($this->data['uid']);
         }
     }
diff --git a/plugins/libkolab/lib/kolab_storage_cache.php b/plugins/libkolab/lib/kolab_storage_cache.php
index a800e58d..cdb373fd 100644
--- a/plugins/libkolab/lib/kolab_storage_cache.php
+++ b/plugins/libkolab/lib/kolab_storage_cache.php
@@ -717,7 +717,7 @@ class kolab_storage_cache
     {
         if (!isset($this->uid2msg[$uid])) {
             // use IMAP SEARCH to get the right message
-            $index = $this->imap->search_once($this->folder->name, ($deleted ? '' : 'UNDELETED ') . 'HEADER SUBJECT ' . $uid);
+            $index = $this->imap->search_once($this->folder->name, ($deleted ? '' : 'UNDELETED ') . 'HEADER SUBJECT "' . $uid. '"');
             $results = $index->get();
             $this->uid2msg[$uid] = $results[0];
         }