diff --git a/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java b/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
index b379c492..7b39fd1b 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
@@ -195,6 +195,7 @@ public class DexFile {
 
     private void writeTo(@Nonnull String path) throws IOException {
         RandomAccessFile raf = new RandomAccessFile(path, "rw");
+        raf.setLength(0);
         try {
             int dataSectionOffset = getDataSectionOffset();
             DexWriter headerWriter  = outputAt(raf, 0);