diff --git a/profiles/desktop.nix b/profiles/desktop.nix
index f5436e8..b2d9402 100644
--- a/profiles/desktop.nix
+++ b/profiles/desktop.nix
@@ -40,7 +40,11 @@
   programs.niri.enable = true;
   programs.nix-ld.enable = true;
 
+  # Wayland-native polkit agent. niri-flake's NixOS module also installs
+  # polkit-kde-agent-1 as a user service, and only one agent may register per
+  # session, so the loser dies with "An authentication agent already exists".
   security.soteria.enable = true;
+  systemd.user.services.niri-flake-polkit.enable = false;
 
   environment.systemPackages = with pkgs; [
     git