Microsoft Windows XP Home Edition (for x64 systems)

Windows XP Home Edition (for x64 systems)  is a canceled project that only had 3 builds under its development. Development started on June 2, 2004, and halted development on September 2, 2005. This version of Windows XP was meant for home computers with an x64 processor. Some developers said that an x64 version of Windows XP Home Edition was really a not really needed project. Microsoft built 3 builds for testing and saw a lot of bugs due to the added features. Microsoft stated on 5 September 2005 that they halted the development due to many bugs from the registry (added x64 compatibility, and x86 compatibility for programs) and also system problems that could malfunction the BIOS from not detecting the RAM (even if it is compatible) and even the processor.

Builds on the development

 * June 2, 2004: Build x642000: Microsoft Codename Family (based on Windows Server (x64) beta 1) (developers testing build)
 * August 15, 2005: Build x642001: Microsoft Windows XP (Home x64) (based on Windows Server (x64) test build) (developers testing build 2, rev 1)
 * September 1, 2005: Build x642002: Microsoft Windows XP x64 Home Edition (based on Serverx64) pre-alpha) (developers testing build 2005 r2)

Bill Gates' interview, 2005 November (C|net)
...I am quite disappointed with the failure of Windows XP Home (x64)... Intel wanted to do it, however, it was very buggy.