diff --git a/pkgs/applications/version-management/monotone-viz/mtn-head.nix b/pkgs/applications/version-management/monotone-viz/mtn-head.nix
index 919f17f54617..6693795edd90 100644
--- a/pkgs/applications/version-management/monotone-viz/mtn-head.nix
+++ b/pkgs/applications/version-management/monotone-viz/mtn-head.nix
@@ -5,7 +5,7 @@ rec {
     dbs = ["monotone.ca"];
     selector = "0e9194c89eb87e62ac7d54c7b88b10b94b07fa41";
     branch = "net.venge.monotone-viz.automate";
-    sha256 = "b9189ccd64c02d158517e97bce079e87843e7b1948c5c61c534aa0b885c711ac";
+    sha256 = "d7980c9729b0a58f0dd27768b8eae46b45462fe72a88534b8aa159d889b4d624";
   } + "/";
 
   buildInputs = [ocaml lablgtk libgnomecanvas gtk graphviz glib 
diff --git a/pkgs/build-support/fetchmtn/builder.sh b/pkgs/build-support/fetchmtn/builder.sh
index f39e38168802..68ce69ca6c12 100644
--- a/pkgs/build-support/fetchmtn/builder.sh
+++ b/pkgs/build-support/fetchmtn/builder.sh
@@ -44,3 +44,8 @@ fi;
 
 stopNest
 
+header "clearing _MTN in the output"
+
+rm -rf "$out/_MTN"
+
+stopNest