diff --git a/nixos/modules/services/x11/display-managers/default.nix b/nixos/modules/services/x11/display-managers/default.nix
index 7e05cd84be6..991043d73c6 100644
--- a/nixos/modules/services/x11/display-managers/default.nix
+++ b/nixos/modules/services/x11/display-managers/default.nix
@@ -161,7 +161,11 @@ let
       exit 0
     '';
 
-  mkDesktops = names: pkgs.runCommand "desktops" {}
+  mkDesktops = names: pkgs.runCommand "desktops"
+    { # trivial derivation
+      preferLocalBuild = true;
+      allowSubstitutes = false;
+    }
     ''
       mkdir -p $out
       ${concatMapStrings (n: ''
diff --git a/pkgs/applications/window-managers/xmonad/wrapper.nix b/pkgs/applications/window-managers/xmonad/wrapper.nix
index cb02a214d5b..e8dc0b1fdac 100644
--- a/pkgs/applications/window-managers/xmonad/wrapper.nix
+++ b/pkgs/applications/window-managers/xmonad/wrapper.nix
@@ -13,4 +13,8 @@ in stdenv.mkDerivation {
       --set NIX_GHC "${xmonadEnv}/bin/ghc" \
       --set XMONAD_XMESSAGE "${xmessage}/bin/xmessage"
   '';
+
+  # trivial derivation
+  preferLocalBuild = true;
+  allowSubstitutes = false;
 }