diff --git a/flake.nix b/flake.nix
index 1e445b5..67f4e52 100644
--- a/flake.nix
+++ b/flake.nix
@@ -163,6 +163,7 @@
         home-manager = {
           useGlobalPkgs = true;
           useUserPackages = true;
+          backupFileExtension = "hm.bak";
           inherit users;
           extraSpecialArgs = {
             inherit inputs outputs vars nixpkgs home-manager;