diff --git a/pkgs/servers/dict/default.nix b/pkgs/servers/dict/default.nix
index 0e6c39ec924..2093d54b065 100644
--- a/pkgs/servers/dict/default.nix
+++ b/pkgs/servers/dict/default.nix
@@ -13,7 +13,11 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ bison flex libtool which ];
 
-  enableParallelBuilding = true;
+  # Makefile(.in) contains "clientparse.c clientparse.h: clientparse.y" which
+  # causes bison to run twice, and break the build when this happens in
+  # parallel.  Test with "make -j clientparse.c clientparse.h".  The error
+  # message may be "mv: cannot move 'y.tab.c' to 'clientparse.c'".
+  enableParallelBuilding = false;
 
   patchPhase = "patch -p0 < ${./buildfix.diff}";
   configureFlags = [