diff --git a/FeedsExcelParser.inc b/FeedsExcelParser.inc
index 602bef3..ece15a7 100644
--- a/FeedsExcelParser.inc
+++ b/FeedsExcelParser.inc
@@ -117,11 +117,6 @@ class FeedsExcelParser extends FeedsParser{
           }
           $column++;
         }
-        // A special case.  We need to ensure that the GUID column has a value
-        // defined, even if that value is the empty string.
-        if(count($row_values) && $column < count($this->state->column_names) && !isset($row_values['GUID']) && array_search('GUID', $this->state->column_names)){
-          $row_values['GUID'] = '';
-        }
         if(!isset($this->state->column_names)){
           // Loop through the headers we have been provided with, and convert them
           // to the exact case/capitalisation as the mappings that the importer
@@ -143,6 +138,11 @@ class FeedsExcelParser extends FeedsParser{
             $rows[] = $row_values;
           }
         }
+        // A special case.  We need to ensure that the GUID column has a value
+        // defined, even if that value is the empty string.
+        if(count($row_values) && $column < count($this->state->column_names) && !isset($row_values['GUID']) && array_search('GUID', $this->state->column_names)){
+          $row_values['GUID'] = '';
+        }
         if(!$source_config['use_chunk_reader'] && $num_rows_pulled >= (isset($source_config['chunk_size']) ? $source_config['chunk_size'] : variable_get('feeds_process_limit', FEEDS_PROCESS_LIMIT))){
           break;
         }