diff --git a/opf/_common/checkpoint_download.py b/opf/_common/checkpoint_download.py
index 743f889..4d1c6f5 100644
--- a/opf/_common/checkpoint_download.py
+++ b/opf/_common/checkpoint_download.py
@@ -76,13 +76,16 @@ def _promote_original_subtree(target: Path) -> None:
             f"Downloaded checkpoint is missing expected subtree: {original_dir}"
         )
 
-    for path in original_dir.iterdir():
+    entries = list(original_dir.iterdir())
+    for path in entries:
         destination = target / path.name
         if destination.exists():
             raise RuntimeError(
                 "Cannot promote downloaded checkpoint file because destination "
                 f"already exists: {destination}"
             )
+    for path in entries:
+        destination = target / path.name
         shutil.move(str(path), str(destination))
     original_dir.rmdir()