diff --git a/lib/default.nix b/lib/default.nix
index b41bfb3..09c10ed 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -8,7 +8,7 @@ let
     home-manager = {
       useGlobalPkgs = true;
       useUserPackages = true;
-      backupFileExtension = "backup";
+      backupFileExtension = "bak";
       extraSpecialArgs = {
         inherit inputs username;
       };
diff --git a/modules/darwin/default.nix b/modules/darwin/default.nix
index 78aa0a2..287b36c 100644
--- a/modules/darwin/default.nix
+++ b/modules/darwin/default.nix
@@ -8,9 +8,11 @@
   programs.fish.enable = true;
 
   # ── User ───────────────────────────────────────────
+  users.knownUsers = [ username ];
   users.users.${username} = {
     home = "/Users/${username}";
     shell = pkgs.fish;
+    uid = 501;
   };
 
   # ── Fonts ──────────────────────────────────────────