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Enable case sensitive behavior with Windows XP and Interix Subsystem or SFU

Support for Windows XP has ended

Microsoft ended support for Windows XP on April 8, 2014. This change has affected your software updates and security options. Learn what this means for you and how to stay protected.

Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry
If you use Interix 2.2 on a computer that runs Microsoft Windows XP, you cannot use files named like "abc.txt", "Abc.txt" and "ABC.TXT" in the samedirectory. This issue may also occur if you install Windows Services for Unix 3.0 and do not change the default behavior of Windows XP during SFU 3.0 setup. This issue does not occur if you use Window NT or Windows 2000.
By default, the Windows XP subsystems other than the Win32 subsystem are case-preserving but not case-sensitive. However, by default, in earlier versions of Windows the subsystems other than the Win32 subsystem are case-sensitive.
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To change the behavior of Windows XP after you install Windows Services for Unix or when you use Interix 2.2, you must add the following registry key, and then restart the computer:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Kernel

Value Name:

Data Type: REG_DWORD
Value Data: 0 (Case sensitive)
To support standard UNIX behavior, Windows Services for UNIX Setup permits you to change the default Windows XP behavior for non-Win32 subsystems when you install the base utilities (that install the Interix subsystem) or Server for NFS. If you turn on case sensitivity, and later remove Server for NFS and the base utilities, Windows Services for UNIX Setup restores the default, case-insensitive behavior of the non-Win32 subsystems.

Article ID: 817921 - Last Review: 04/15/2005 06:47:28 - Revision: 4.2

  • Microsoft Interix 2.2 Standard Edition
  • Microsoft Windows XP Professional
  • Microsoft Windows Services for UNIX 3.0 Standard Edition
  • Microsoft Windows Services for Unix 2.2
  • kbunixservice kbhowto KB817921