How to check if an hard drive is Advanced Format (AF) disk in Windows 7 or Windows Server 2008 R2


Article ID: 156874


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This article describes how to check if a hard drive is an Advanced Format (AF) disk or legacy 512 native in computers with Windows 7 or Windows Server 2008 R2 installed.


1. Open a command prompt (Start > Run > cmd)

2. Enter the command:

fsutil fsinfo ntfsinfo <drive letter>:

3. In the output you will find the value for "Bytes Per Physical Sector", which can be one of the following:

512 - for Legacy 512 native drives
4096 - for Advanced Format (AF) drives
<Not Supported> - if the hardware or driver does not support the IOCTL_STORAGE_QUERY_PROPERTY control code


  • The hotfix from Microsoft KB982018 may be required.
  •  Support for Advanced Format disks relies on the disk reporting itself as having 4KB physical sectors, and relies on the Storage Driver reporting the physical sector size.


 External reference:

An update that improves the compatibility of Windows 7 and Windows Server 2008 R2 with Advanced Format Disks is available, see the following article.