diff --git a/library/src/android/support/multidex/MultiDexExtractor.java b/library/src/android/support/multidex/MultiDexExtractor.java
index 177279a..6d09245 100644
--- a/library/src/android/support/multidex/MultiDexExtractor.java
+++ b/library/src/android/support/multidex/MultiDexExtractor.java
@@ -356,6 +356,10 @@
             } finally {
                 out.close();
             }
+            if (!tmp.setReadOnly()) {
+                throw new IOException("Failed to mark readonly \"" + tmp.getAbsolutePath() +
+                        "\" (tmp of \"" + extractTo.getAbsolutePath() + "\")");
+            }
             Log.i(TAG, "Renaming to " + extractTo.getPath());
             if (!tmp.renameTo(extractTo)) {
                 throw new IOException("Failed to rename \"" + tmp.getAbsolutePath() +