Windows NT 6.0

Windows NT 6.0 (codename Odyssey) was released to manufacturing on September 7, 2006.

Development
In 2002, Microsoft was working on Codename Longhorn, based on Windows XP's kernel. The Windows NT development team worked on the respective version, 6.0.

Before Reset
The first known Windows NT 6.0 build was compiled on January 5, 2003. It was basically the same as Windows NT 5.1, however with Longhorn's kernel, some Longhorn features and the build number 3520. It possessed the Plex theme in a later build. Later, with the Start button modification in Longhorn, the Start button logo was changed to Longhorn's current one, however it was not zoomed in. With the Desktop Composition Engine in development, it was supposed to be slimmed down, so the DCE and Windows Sidebar were not included by default. Later with the introduction of Slate, the Start button icon stayed at the left with text and the colored logo again, without a centered logo. Jade was also included.

After Reset
When Longhorn development was reset, Odyssey development was too. It was paused for a while, but the project was revived, based on Windows NT 5.5. The normal "Aero" theme (which is actually Basic) was the same except for the introduction of the circular Start button into Vista, which the NT 6.0 Start button had a similar look but in Windows XP's pill shape, with text, and no centered logo. The Start button logo, however, was the white one from Vista builds at the time, which was only seen with the Classic theme. Windows NT 6.0 was released in 2006 with Standard, Professional and Enterprise editions.

Setup
Setup has a similar appearance to Vista builds from the time, however you can select individual features to install during Setup, like with Windows 9x. Of course, this can be done after Setup using the Add/Remove Windows Features unit of Control Panel.

Appearance
Windows NT 6.0 has a similar appearance to Vista builds 5259 through 5456. The Desktop Window Manager isn't included by default, not even in the features to add/remove, but it's capable of running it through some modifications.