diff --git a/src/gen/mkillum.c b/src/gen/mkillum.c
index e37e98e27..4fa227c9f 100644
--- a/src/gen/mkillum.c
+++ b/src/gen/mkillum.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: mkillum.c,v 2.42 2016/09/15 22:34:41 greg Exp $";
+static const char RCSid[] = "$Id: mkillum.c,v 2.43 2020/07/20 15:54:29 greg Exp $";
 #endif
 /*
  * Make illum sources for optimizing rendering process
@@ -177,7 +177,9 @@ quit(ec)			/* make sure exit is called */
 int	ec;
 {
 	if (ray_pnprocs > 0)	/* close children if any */
-		ray_pclose(0);		
+		ray_pclose(0);
+	else if (ray_pnprocs < 0)
+		_exit(ec);	/* avoid flush() in child */
 	exit(ec);
 }
 
diff --git a/src/rt/rcontrib.c b/src/rt/rcontrib.c
index 42a3cdbd1..9c029a4ca 100644
--- a/src/rt/rcontrib.c
+++ b/src/rt/rcontrib.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: rcontrib.c,v 2.35 2019/04/07 16:39:39 greg Exp $";
+static const char RCSid[] = "$Id: rcontrib.c,v 2.36 2020/07/20 15:54:29 greg Exp $";
 #endif
 /*
  * Accumulate ray contributions for a set of materials
@@ -179,6 +179,8 @@ quit(			/* quit program */
 {
 	if (nchild > 0)		/* close children if any */
 		end_children(code != 0);
+	else if (nchild < 0)
+		_exit(code);	/* avoid flush() in child */
 	exit(code);
 }
 
diff --git a/src/rt/rtrace.c b/src/rt/rtrace.c
index 59a11e781..a39bd6a38 100644
--- a/src/rt/rtrace.c
+++ b/src/rt/rtrace.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: rtrace.c,v 2.98 2020/06/16 17:58:11 greg Exp $";
+static const char	RCSid[] = "$Id: rtrace.c,v 2.99 2020/07/20 15:54:29 greg Exp $";
 #endif
 /*
  *  rtrace.c - program and variables for individual ray tracing.
@@ -92,8 +92,10 @@ quit(			/* quit program */
 {
 	if (ray_pnprocs > 0)	/* close children if any */
 		ray_pclose(0);		
+	else if (ray_pnprocs < 0)
+		_exit(code);	/* avoid flush() in child */
 #ifndef  NON_POSIX
-	else if (!ray_pnprocs) {
+	else {
 		headclean();	/* delete header file */
 		pfclean();	/* clean up persist files */
 	}
diff --git a/src/util/ranimove.c b/src/util/ranimove.c
index c0bff7095..c0304e253 100644
--- a/src/util/ranimove.c
+++ b/src/util/ranimove.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: ranimove.c,v 3.18 2016/04/18 22:39:13 greg Exp $";
+static const char RCSid[] = "$Id: ranimove.c,v 3.19 2020/07/20 15:54:29 greg Exp $";
 #endif
 /*
  *  Radiance object animation program
@@ -193,7 +193,9 @@ void
 quit(int ec)			/* make sure exit is called */
 {
 	if (ray_pnprocs > 0)	/* close children if any */
-		ray_pclose(0);		
+		ray_pclose(0);
+	else if (ray_pnprocs < 0)
+		_exit(ec);	/* avoid flush in child */
 	exit(ec);
 }
 
diff --git a/src/util/rsensor.c b/src/util/rsensor.c
index b307f757c..5b84c5ab9 100644
--- a/src/util/rsensor.c
+++ b/src/util/rsensor.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: rsensor.c,v 2.18 2015/06/09 21:34:15 greg Exp $";
+static const char RCSid[] = "$Id: rsensor.c,v 2.19 2020/07/20 15:54:29 greg Exp $";
 #endif
 
 /*
@@ -77,7 +77,9 @@ quit(ec)			/* make sure exit is called */
 int	ec;
 {
 	if (ray_pnprocs > 0)	/* close children if any */
-		ray_pclose(0);		
+		ray_pclose(0);
+	else if (ray_pnprocs < 0)
+		_exit(ec);	/* avoid flush in child */
 	exit(ec);
 }