Once the partnership with IBM faltered with the development of OS/2, Microsoft went alone and Windows NT was born back in 1993. Microsoft’s first true 32-bit operating system, it generally was to be seen only on high-end desktop workstations and servers. The first version was 3.1, to match the versioning of the more consumer orientated Windows 3.1 that was released a year prior. There was two editions – one named simply Windows NT 3.1 for workstation use, and the other named Windows NT 3.1 Advanced Server which obviously suggests for servers on a network. A relative lack of 32-bit software and higher system requirements meant success was limited and most of the attention was towards MS-DOS and Windows 3.1.
Installing Windows NT 3.1 is certainly not the easiest Windows to install into VirtualBox due to a few limitations. It’s very easy for the VM to crash or for NT 3.1 to complain about the hardware due to what was available at the time. Back then, Intel had been beta testing their new Pentium processors to supersede the 486, and introduced the CPUID instruction set which allows software to identify the CPU’s features.
By default, it’s a no go when installing unless Setup detects specific 386, 486, or Pentium processors.