diff --git a/contrib/pg_upgrade/dump.c b/contrib/pg_upgrade/dump.c
index b905ab084d7337dc4fc5c5b064e09c9c3ab00552..148dfb70c1805c0aa6ff3a961623bacbcf5273d4 100644
--- a/contrib/pg_upgrade/dump.c
+++ b/contrib/pg_upgrade/dump.c
@@ -58,14 +58,20 @@ split_old_dump(void)
 	char		filename[MAXPGPATH];
 	bool		suppressed_username = false;
 
+
+	/* 
+	 * Open all files in binary mode to avoid line end translation on Windows,
+	 * boths for input and output.
+	 */
+
 	snprintf(filename, sizeof(filename), "%s", ALL_DUMP_FILE);
-	if ((all_dump = fopen(filename, "r")) == NULL)
+	if ((all_dump = fopen(filename, PG_BINARY_R)) == NULL)
 		pg_log(PG_FATAL, "Could not open dump file \"%s\": %s\n", filename, getErrorText(errno));
 	snprintf(filename, sizeof(filename), "%s", GLOBALS_DUMP_FILE);
-	if ((globals_dump = fopen_priv(filename, "w")) == NULL)
+	if ((globals_dump = fopen_priv(filename, PG_BINARY_W)) == NULL)
 		pg_log(PG_FATAL, "Could not write to dump file \"%s\": %s\n", filename, getErrorText(errno));
 	snprintf(filename, sizeof(filename), "%s", DB_DUMP_FILE);
-	if ((db_dump = fopen_priv(filename, "w")) == NULL)
+	if ((db_dump = fopen_priv(filename, PG_BINARY_W)) == NULL)
 		pg_log(PG_FATAL, "Could not write to dump file \"%s\": %s\n", filename, getErrorText(errno));
 
 	current_output = globals_dump;