diff --git a/field_collection.install b/field_collection.install
index 91edfbb..41c64ea 100644
--- a/field_collection.install
+++ b/field_collection.install
@@ -277,7 +277,12 @@ function field_collection_update_7004() {
       $revision_id_column = sprintf('%s_revision_id', $field_name);
 
       // Add index on revision_id column.
-      db_add_index($table, $revision_id_column, array($revision_id_column));
+      try {
+        db_add_index($table, $revision_id_column, array($revision_id_column));
+      }
+      catch (DatabaseSchemaObjectExistsException $ex) {
+        watchdog('field_collection', $ex->getMessage());
+      }
     }
   }
 }