--- a/include/git/filemimetype/FileMimeType_Extension.class.php
+++ b/include/git/filemimetype/FileMimeType_Extension.class.php
@@ -52,7 +52,7 @@
 	 */
 	public function Valid()
 	{
-		return !GitPHP_Util::IsWindows();
+		return true;
 	}
 
 }