What was the first version of Windows NT, released in 1993?

The first version of Windows NT, released in 1993, was Windows NT 3.1.

Microsoft announced Windows NT and Windows NT Advanced Server 3.1 in May 1993, then released the operating system later that year. The “3.1” numbering connected it visually with Windows 3.1, but NT was a substantially different operating-system family built for stronger security, reliability, portability, and business networking.

Windows NT 3.1 used a 32-bit architecture and introduced the Win32 application programming interface, while retaining a graphical style familiar to users of consumer Windows. Its development was led by a Microsoft team working with ideas and expertise associated with former Digital Equipment Corporation engineer Dave Cutler.

A common mix-up is Windows 3.1, which preceded NT but was not an NT release. Windows NT 4.0 arrived in 1996 and brought the Windows 95-style desktop to the NT line. Windows 2000 was later still, serving as the successor to Windows NT 4.0 Workstation and Server.