diff --git a/src/main/java/org/apache/solr/benchmarks/indexing/IndexBatchSupplier.java b/src/main/java/org/apache/solr/benchmarks/indexing/IndexBatchSupplier.java
index dbd02b81..e7230fd4 100644
--- a/src/main/java/org/apache/solr/benchmarks/indexing/IndexBatchSupplier.java
+++ b/src/main/java/org/apache/solr/benchmarks/indexing/IndexBatchSupplier.java
@@ -106,6 +106,7 @@ private Future<?> startWorker(DocReader docReader) {
     }
 
 	private String computeBatchFilename(IndexBenchmark benchmark, Map<String, AtomicInteger> batchCounters, String shard) {
+		if (benchmark.prepareBinaryFormat == null) return null;
 		String batchFilename = null;
 		String tmpDir = "tmp/"+benchmark.name;
 		try {