diff --git a/nixos/modules/misc/man-db.nix b/nixos/modules/misc/man-db.nix
index dc6af4fe9692..50ae6d790789 100644
--- a/nixos/modules/misc/man-db.nix
+++ b/nixos/modules/misc/man-db.nix
@@ -82,6 +82,7 @@ in
           pkgs.runCommand "man-cache"
             {
               nativeBuildInputs = [ buildPackage ];
+              preferLocalBuild = true;
             }
             ''
               echo "MANDB_MAP ${cfg.manualPages}/share/man $out" > man.conf