diff --git a/api.go b/api.go
index 17c01637b..eae4283c4 100644
--- a/api.go
+++ b/api.go
@@ -323,21 +323,21 @@ func (api *API) ImportRoaring(ctx context.Context, indexName, fieldName string,
 					if len(viewData) == 0 {
 						return fmt.Errorf("no data to import for view: %s", viewName)
 					}
-					// must make a copy of data to operate on locally.
-					// field.importRoaring changes data
 					fileMagic := uint32(binary.LittleEndian.Uint16(viewData[0:2]))
-					if fileMagic == roaring.MagicNumber { // if pilosa roaring
+					if fileMagic == roaring.MagicNumber { // if pilosa roaring format
 						err = field.importRoaring(viewData, shard, viewName, req.Clear)
 						if err != nil {
-							return err
+							return errors.Wrap(err,"import pilosa roaring")
 						}
 
 					} else {
+					// must make a copy of data to operate on locally on standard roaring format.
+					// field.importRoaring changes the standard roaring run format to pilosa roaring
 						data := make([]byte, len(viewData))
 						copy(data, viewData)
 						err = field.importRoaring(data, shard, viewName, req.Clear)
 						if err != nil {
-							return err
+							return errors.Wrap(err,"import standard roaring")
 						}
 					}
 				}