diff --git a/oscar/configuration.nix b/oscar/configuration.nix
index 42f9f8f..896bcbf 100644
--- a/oscar/configuration.nix
+++ b/oscar/configuration.nix
@@ -120,6 +120,7 @@
   users.users.chandler.isNormalUser = true;
   users.users.chandler.description = "Chandler Swift";
   users.users.chandler.extraGroups = [ "networkmanager" "wheel" "dialout" "cdrom" "plugdev" ];
+  home-manager.backupFileExtension = "backup";
   home-manager.users.chandler = { pkgs, ... }: {
 
     nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [