diff --git a/src/main/java/net/openhft/chronicle/map/FilePerKeyMap.java b/src/main/java/net/openhft/chronicle/map/FilePerKeyMap.java
old mode 100644
new mode 100755
index a273b659e..e172da819
--- a/src/main/java/net/openhft/chronicle/map/FilePerKeyMap.java
+++ b/src/main/java/net/openhft/chronicle/map/FilePerKeyMap.java
@@ -203,12 +203,19 @@ public class FilePerKeyMap implements Map<String, String>, Closeable {
         } catch (IOException e) {
             throw new AssertionError(e);
         }
-        tmpFile.renameTo(file);
+        try {
+            Files.move(tmpFile.toPath(), file.toPath(), StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.ATOMIC_MOVE);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
     }
 
     private void deleteFile(Path path) {
-        File key = path.toFile();
-        key.delete();
+        try {
+            Files.deleteIfExists(path);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
     }
 
     public void close() {
@@ -297,7 +304,7 @@ public class FilePerKeyMap implements Map<String, String>, Closeable {
                                 continue;
                             }
 
-                             if (kind == StandardWatchEventKinds.ENTRY_CREATE) {
+                            if (kind == StandardWatchEventKinds.ENTRY_CREATE) {
                                 Path p = dirPath.resolve(fileName);
                                 try {
                                     String mapVal = getFileContents0(p);
diff --git a/src/test/java/net/openhft/chronicle/map/FilePerKeyMapTest.java b/src/test/java/net/openhft/chronicle/map/FilePerKeyMapTest.java
old mode 100644
new mode 100755
index 8ec390f60..42ed147d8
--- a/src/test/java/net/openhft/chronicle/map/FilePerKeyMapTest.java
+++ b/src/test/java/net/openhft/chronicle/map/FilePerKeyMapTest.java
@@ -31,13 +31,15 @@ public class FilePerKeyMapTest {
     public void testMapMethods() throws InterruptedException {
         String val = map.put("one", "test1");
         assertEquals(val, null);
-        Thread.sleep(5);
+        Thread.sleep(10);
 
         //After the entry has been written the value returned should be
         //the previous value
         val = map.put("one", "test2");
         assertEquals(val, "test1");
 
+        Thread.sleep(10);
+
         //Check that get returns the latest value
         val = map.get("one");
         assertEquals("test2", val);