diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 8320dd1c4..3209f8c33 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -726,7 +726,7 @@ void LocalDerivationGoal::startBuilder()
     Path logFile = openLogFile();
 
     /* Create a pipe to get the output of the builder. */
-    //builderOut.create();
+    builderOut.create();
 
     builderOut.readSide = posix_openpt(O_RDWR | O_NOCTTY);
     if (!builderOut.readSide)