diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
index 5247a2991b1b..7cc606561404 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
@@ -471,7 +471,7 @@ def upgrade_channels(all: bool = False) -> None:
     that has a `.update-on-nixos-rebuild` file) or all.
     """
     for channel_path in Path("/nix/var/nix/profiles/per-user/root/channels/").glob("*"):
-        if (
+        if channel_path.is_dir() and (
             all
             or channel_path.name == "nixos"
             or (channel_path / ".update-on-nixos-rebuild").exists()
diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
index 317821d5fea0..093cba93ef36 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
@@ -561,7 +561,8 @@ def test_switch_to_configuration(mock_run: Any, monkeypatch: Any) -> None:
         Path("/nix/var/nix/profiles/per-user/root/channels/home-manager"),
     ],
 )
-def test_upgrade_channels(mock_glob: Any) -> None:
+@patch(get_qualified_name(n.Path.is_dir, n), autospec=True, return_value=True)
+def test_upgrade_channels(mock_is_dir: Any, mock_glob: Any) -> None:
     with patch(get_qualified_name(n.run_wrapper, n), autospec=True) as mock_run:
         n.upgrade_channels(False)
     mock_run.assert_called_with(["nix-channel", "--update", "nixos"], check=False)