OpenNT – Windows NT 4.5

(This is a guest post from Tenox)

Just stumbled across this: someone has forked Windows NT 4.0 and created an open source version of it. But wait, forked what? Windows source code doesn’t live on Github. Is it ReactOS? No! Upon some digging, it was apparently born from the leaked source code of NT4.0, some W2K bits and 2003 WRK…

Enter NT version 4.5:

NT45Test-2015-04-27-18-20-37More screenshots here:

The main project site:

Looking at activity the project seems to be alive and well. There is some background information and discussion going on BetaArchive for those interested.

I wonder what Microsoft has to say about this 🙂

EDIT* for those from the future, you may be interested in this followup – OpenNT 4.5 revisited, where it’s compiled and run!

23 thoughts on “OpenNT – Windows NT 4.5

  1. I installed it on Qemu… It’s NT 4.0 all right. I haven’t tried any MS service packs or anything exciting. And I see from the wiki notes it’s currently unbuildable.

    But interesting none the less!

      • Thanks. I know about NT 4 limitations. Here is how I try to run it under x64 Win7:
        qemu-system-i386 -L . -hda NT4.disk -cpu pentium -soundhw all -cdrom NT45Wks_x86fre-sr687.iso -boot d -m 512

        but after install finishes coping files the system crash with bluescreen every time.

        • I’m using, which has my hook for control+alt+d does a CAD to make NT more usable.

          I’m going to use the install ISO NT45Wks_x86fre-sr687.iso

          Then make a 2GB VMDK:
          qemu-img.exe create -f vmdk opennt.vmdk 2G

          Then to kick off the install:
          qemu-system-i386.exe -L pc-bios -m 16 -soundhw sb16,adlib -hda opennt.vmdk -net nic,model=pcnet -net user -cdrom NT45Wks_x86fre-sr383.iso

          From there I just chose the standard VGA install.

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