Skip to main content
NetApp Knowledge Base

Does Clustered ONTAP support Non-Unicode SMB requests?

Last Updated:


Applies to

  • ONTAP 9
  • CIFS / SMB


  • ONTAP does not support Non-unicode SMB requests
    • These specifically come from client using SMB version 1 or older variants
    • NetApp and Microsoft strongly discourage the use of the SMBv1 protocol due to its numerous known security issues.

Additional Information

To determine if SMB requests are using a non-unicode format, a packet trace and AutoSupport is required

  • EMS alert only available in ONTAP 9.3 and later (example below)

Tue Oct 22 10:15:44 CDT [cluster-01: kernel: Nblade.cifsNonUnicodeRequest:error]: Vserver ID 1 rejected non-unicode request from client IP:


NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.