diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/services.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/services.py
index ba8effa134a1..933c2f8de10e 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/services.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/services.py
@@ -321,10 +321,10 @@ def build_and_activate_system(
             grouped_nix_args=grouped_nix_args,
         )
 
-    current_config = Path("/run/current-system").readlink()
+    current_config = Path("/run/current-system")
     if args.diff:
         if current_config.exists():
-            nix.diff_closures(current_config=current_config, new_config=path_to_config, target_host=target_host)
+            nix.diff_closures(current_config=current_config.readlink(), new_config=path_to_config, target_host=target_host)
         else:
             logger.warning(f"missing '{str(current_config)}', skipping configuration diff...")