Development of Windows Vista

The development of Windows Vista started in May 2001, around the time Windows XP was still in development.

2001-2002: Early development (pre-reset builds)

The development started with build 4093 (Milestone 3 build date of August 19, 2004). It added a new theme called "Plex" and it added features like the "sidebar" on the right, a predecessor of Windows Sidebar, a logon screen clock, and more. Build 4042 (Lab06) added the "Slate" and "Aero" themes and in build 4074, Windows Vista-ish icons were added. But then, build 4093 came out, which is the last pre-reset build of Windows Longhorn, due to bugs.

Mid-2004 to mid-2005: Development "reset" (post-reset builds)

Microsoft started over from scratch, and released builds 5000, 3790, and 5001. Later in 2005, build 5048 came out, adding the Aero theme again. A search bar was added in the start menu.

Mid-2005 to November 2006: Windows Vista

In Build 5112, the name was changed from Windows Longhorn to Windows Vista, another Aero theme was added and so on. In Windows Vista Build 5259, the start button was replaced with a orb, the setup was also changed. In Windows Vista build 5536, the Aero theme got changed again and some new functions were added.

Pre-RTM

Windows Vista Build 5738 marks the start of the Pre-RTM phase. Build 6000.16385 is the final, latest Windows Vista Pre-RTM build.

RTM

Build 6000.16386 marks the end of the development of Vista.