diff --git a/core/modules/file/migration_templates/d6_file.yml b/core/modules/file/migration_templates/d6_file.yml
index 6df20b5..42be2d0 100644
--- a/core/modules/file/migration_templates/d6_file.yml
+++ b/core/modules/file/migration_templates/d6_file.yml
@@ -40,7 +40,9 @@ process:
       - '@source_full_path'
       - '@destination_full_path'
   filemime: filemime
-  filesize: filesize
+  # filesize is dynamically computed when file entities are saved, so there is
+  # no point in migrating it.
+  # filesize: filesize
   status: status
   changed: timestamp
   uid: uid