diff --git a/src/main/java/com/eactive/ext/kjb/ums/EmailJob.java b/src/main/java/com/eactive/ext/kjb/ums/EmailJob.java
index dc4d4fe..fb27084 100644
--- a/src/main/java/com/eactive/ext/kjb/ums/EmailJob.java
+++ b/src/main/java/com/eactive/ext/kjb/ums/EmailJob.java
@@ -50,7 +50,7 @@ public class EmailJob {
         this.messageRequest = messageRequest;
         this.prop = prop;
 
-        String filename = messageRequest.getServiceId() + "_" + DateTimeFormatter.ofPattern("yyyyMMddHHmmss").format(now);
+        String filename = messageRequest.getServiceId() + "_" + DateTimeFormatter.ofPattern("yyyyMMddHHmmss").format(now) + ".dat";
         this.eaiFilePath = Paths.get(prop.getUmsEaiBatchSendDir(), filename);
         this.backupFilePath = Paths.get(prop.getUmsEaiBatchBackupDir(), filename);
         this.failedFilePath = Paths.get(prop.getUmsEaiBatchBackupDir(), filename + ".failed");