What is ntdll.dll?

The ntdll.dll file is a file created by Microsoft with a description of “NT Layer DLL” and is the file containing NT kernel functions.

The ntdll.dll file is located in the c:\windows\system32 or c:\winnt\system32 directory, also found in the c:\i386 directory.

Is this file a security threat?

The ntdll.dll is flagged as a critical security risk in the Microsoft security bulletin MS03-07 dated on March 17, 2003. If you have all the latest updates for your version of Windows, you should not be affected by this security risk.

Is this file a spyware, trojan, or virus?

The ntdll.dll file included with Microsoft Windows is not spyware, a trojan, or a virus. However, like any file on your computer, it can become corrupted by a virus or trojan. Antivirus programs can detect and clean this file if it’s infected. Because this file is part of Windows, users should never delete or remove this file. If they think it is infected, let the antivirus program handle it.

Can I delete this file?

No, this is a file required by Windows and deleting the file causes errors with Windows.

I’m getting an error with this file in Internet Explorer

Users who are encountering an error with this file while in Microsoft Internet Explorer can often resolve the issue by removing any third-party add-ons. For additional information about removing Internet Explorer add-ons, and other basic troubleshooting steps, see our basic Microsoft Internet Explorer troubleshooting page.

  • Basic Microsoft Internet Explorer troubleshooting.
  • Windows STOP: unknown hard error with the ntdll.dll file.
  • See our dll and file definitions for further information and related links.
  • Microsoft Windows help and support.