diff --git a/lib/ext/Syncroton/Command/Sync.php b/lib/ext/Syncroton/Command/Sync.php
--- a/lib/ext/Syncroton/Command/Sync.php
+++ b/lib/ext/Syncroton/Command/Sync.php
@@ -830,6 +830,14 @@
                         
                         $commands->appendChild($add);
                         
+                        $newContentStates[] = new Syncroton_Model_Content(array(
+                            'device_id'        => $this->_device,
+                            'folder_id'        => $collectionData->folder,
+                            'contentid'        => $serverId,
+                            'creation_time'    => $this->_syncTimeStamp,
+                            'creation_synckey' => $collectionData->syncState->counter + 1
+                        ));
+
                         $collectionChanges++;
                     } catch (Syncroton_Exception_MemoryExhausted $seme) {
                         // continue to next entry, as there is not enough memory left for the current entry
@@ -844,16 +852,11 @@
                             $this->_logger->warn(__METHOD__ . '::' . __LINE__ . " unable to convert entry to xml: " . $e->getMessage());
                         if ($this->_logger instanceof Zend_Log)
                             $this->_logger->debug(__METHOD__ . '::' . __LINE__ . " unable to convert entry to xml: " . $e->getTraceAsString());
+                        // We bump collectionChanges anyways to make sure the windowSize still applies.
+                        $collectionChanges++;
                     }
                     
                     // mark as sent to the client, even the conversion to xml might have failed 
-                    $newContentStates[] = new Syncroton_Model_Content(array(
-                        'device_id'        => $this->_device,
-                        'folder_id'        => $collectionData->folder,
-                        'contentid'        => $serverId,
-                        'creation_time'    => $this->_syncTimeStamp,
-                        'creation_synckey' => $collectionData->syncState->counter + 1
-                    ));
                     unset($serverModifications['added'][$id]);
                 }
 
@@ -890,6 +893,8 @@
                     } catch (Exception $e) {
                         if ($this->_logger instanceof Zend_Log) 
                             $this->_logger->warn(__METHOD__ . '::' . __LINE__ . " unable to convert entry to xml: " . $e->getMessage());
+                        // We bump collectionChanges anyways to make sure the windowSize still applies.
+                        $collectionChanges++;
                     }
 
                     unset($serverModifications['changed'][$id]);    
@@ -915,6 +920,8 @@
                     } catch (Exception $e) {
                         if ($this->_logger instanceof Zend_Log) 
                             $this->_logger->warn(__METHOD__ . '::' . __LINE__ . " unable to convert entry to xml: " . $e->getMessage());
+                        // We bump collectionChanges anyways to make sure the windowSize still applies.
+                        $collectionChanges++;
                     }
                     
                     unset($serverModifications['deleted'][$id]);