diff --git a/pkgs/build-support/fetchhg/default.nix b/pkgs/build-support/fetchhg/default.nix
index 5424c87ded7..bc27516f46d 100644
--- a/pkgs/build-support/fetchhg/default.nix
+++ b/pkgs/build-support/fetchhg/default.nix
@@ -14,4 +14,5 @@ stdenv.mkDerivation {
   outputHash = if (md5 != null) then md5 else sha256;
   
   inherit url tag;
+  preferLocalBuild = true;
 }