Support Policy for Windows booting from external drives

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.


This article discusses the following scenarios:

  • Install Windows to USB drive.
  • Install Windows to Flash Drive(UFD) drive.
  • Install Windows to ESATA drive.
  • Store Windows 7 Native Boot VHD on USB/UFD drive.
More Information

It is unsupported to boot Windows from external devices.  Some of the reasons why this is not supported:

  • Potential Boot Path support issues.
  • Activation issues.
  • You must disable the device write cache or click ‘safe removal’ before unplugging the cable. Otherwise, there could be a data loss.

Some specialized products do support this type of scenario:

Note:  Booting Hyper-V Server 2008 R2 from USB flash drive is only supported for OEM's.

Note This is a "FAST PUBLISH" article created directly from within the Microsoft support organization. The information contained herein is provided as-is in response to emerging issues. As a result of the speed in making it available, the materials may include typographical errors and may be revised at any time without notice. See Terms of Use for other considerations.

Article ID: 2485453 - Last Review: 11/09/2011 15:29:00 - Revision: 8.0

Microsoft Windows XP Professional, Windows Vista Enterprise, Windows Server 2008 Datacenter, Windows Server 2008 Enterprise, Windows Server 2008 Standard, Windows Server 2008 R2 Datacenter, Windows Server 2008 R2 Enterprise, Windows Server 2008 R2 Standard, Windows 7 Enterprise, Windows 7 Home Basic, Windows 7 Home Premium, Windows 7 Professional, Windows 7 Professional for Embedded Systems, Windows 7 Service Pack 1, Windows 7 Starter, Windows 7 Ultimate, Windows 7 Ultimate for Embedded Systems

  • KB2485453