diff --git a/src/integrationtest/org/apache/poi/stress/TestAllFiles.java b/src/integrationtest/org/apache/poi/stress/TestAllFiles.java
index 55777d12ee..4e913e5775 100644
--- a/src/integrationtest/org/apache/poi/stress/TestAllFiles.java
+++ b/src/integrationtest/org/apache/poi/stress/TestAllFiles.java
@@ -86,6 +86,7 @@ public class TestAllFiles {
         DirectoryScanner scanner = new DirectoryScanner();
         scanner.setBasedir(ROOT_DIR);
         scanner.setExcludes(SCAN_EXCLUDES);
+        scanner.setIncludes(new String[]{"**/unknown_properties.msg"});
 
         scanner.scan();
 
diff --git a/src/java/org/apache/poi/poifs/filesystem/POIFSMiniStore.java b/src/java/org/apache/poi/poifs/filesystem/POIFSMiniStore.java
index 9df110ed2d..db49e5b814 100644
--- a/src/java/org/apache/poi/poifs/filesystem/POIFSMiniStore.java
+++ b/src/java/org/apache/poi/poifs/filesystem/POIFSMiniStore.java
@@ -61,12 +61,12 @@ public class POIFSMiniStore extends BlockStore {
         int bigBlockOffset = byteOffset % _filesystem.getBigBlockSize();
 
         // Now locate the data block for it
-        Iterator<ByteBuffer> it = _mini_stream.getBlockIterator();
+        Iterator<Integer> it = _mini_stream.getBlockOffsetIterator();
         for (int i = 0; i < bigBlockNumber; i++) {
             it.next();
         }
 
-        ByteBuffer dataBlock = it.next();
+        ByteBuffer dataBlock = _filesystem.getBlockAt(it.next());
         assert(dataBlock != null);
 
         // Position ourselves, and take a slice