diff --git a/nixosModules/user/default.nix b/nixosModules/user/default.nix
index 06b5d51b..cc49cfa6 100644
--- a/nixosModules/user/default.nix
+++ b/nixosModules/user/default.nix
@@ -11,6 +11,7 @@
     useGlobalPkgs = true;
     useUserPackages = true;
     extraSpecialArgs = inputs;
+    backupFileExtension = "backup";
   };
 
   users.mutableUsers = false;