diff --git a/src/main/java/com/sheepit/client/config/DirectoryManager.java b/src/main/java/com/sheepit/client/config/DirectoryManager.java
index 3096bb4..fe3536f 100644
--- a/src/main/java/com/sheepit/client/config/DirectoryManager.java
+++ b/src/main/java/com/sheepit/client/config/DirectoryManager.java
@@ -150,9 +150,9 @@ public class DirectoryManager {
 				}
 				else {
 					try {
-						String extension = file.getName().substring(file.getName().lastIndexOf('.')).toLowerCase();
-						String name = file.getName().substring(0, file.getName().length() - 1 * extension.length());
-						if (".wool".equals(extension)) {
+						String extension = FilenameUtils.getExtension(file.getName()).toLowerCase();
+						String name = FilenameUtils.removeExtension(file.getName());
+						if ("wool".equals(extension)) {
 							// check if the md5 of the file is ok
 							String md5_local = Utils.md5(file.getAbsolutePath());
 							
@@ -166,7 +166,7 @@ public class DirectoryManager {
 							file.delete();
 						}
 					}
-					catch (StringIndexOutOfBoundsException e) { // because the file does not have an . in his path
+					catch (IllegalArgumentException e) { // because the file does not have an . in his path
 						file.delete();
 					}
 				}