Installing Windows NT 4.0 Workstation under Virtual PC

Windows NT 4.0 Workstation is not particularly difficult to install inside of Virtual PC – however there are a number of small issues that catch people up from time to time.  The first thing to be aware of is that it is best to have installed Virtual PC 2004 Service Pack 1 ( before attempting to install Windows NT 4.0 Workstation – as there were two bugs specific to Windows NT 4.0 installation that were fixed in this service pack (specifically for installing Windows NT on virtual machines with greater than 64mb and installing Windows NT on computers with Prescott class Pentium IV processors).

Before you start installing Windows NT 4.0 Workstation you should decide how many network adapters you want to have in the virtual machine – as changing this after NT installation is actually relatively painful.

Once you have created a new blank virtual machine, and configured the network cards to your liking, you should be able to directly boot the virtual machine off of the Windows NT 4.0 Workstation install CD.

N.B.  Most Windows NT 4.0 Workstation install CDs are bootable.  If your CD is not bootable you will need to use the three boot floppies.  If you do not have the three Windows NT boot floppies – you can create them by running ‘i386winnt32 /OX’ off of the install CD.  Unfortunately – Windows XP actually blocks execution of winnt32 – in order to stop people from accidentally downgrading their system.  This means that you can only create these boot floppies on a DOS through Windows 2000 physical computer / virtual machine.  Doh.

Once you get the installation process running one of the first decisions you will have to make is how to partition the virtual hard disk.  By default Virtual PC will create a blank 16GB virtual hard disk to install on – however this is too large for Windows NT 4.0 to comprehend.  The Windows NT install process will complain about this and then tell you that you have an 8GB drive, but Windows NT 4.0 cannot format an 8GB partition so instead you will need to create a 4GB partition (or smaller) to install Windows NT 4.0 on to.  All of the above restrictions are fixed in later service packs for Windows NT – so you will be able to go back and make a 12GB data partition once you are all done.

You should then be able to go through and follow the default installation options – until you get to the network configuration section.  What you do here depends on how you want to configure your computer.  If you are only ever planning to have one network adapter configured for this virtual machine – you can just hit ‘Start Search’ and it will find the driver for our emulated DEC 21140 network card – and you will be good to go.  If you are planning to have multiple network adapters – then you will find that the ‘in box’ DEC driver does not support multiple network adapters – so instead of hitting ‘Start Search’ you should hit ‘Select from list…’ and then select ‘Have Disk’.  At this stage you will need to capture the following floppy disk image: “%ProgramFiles%Microsoft Virtual PCVirtual Machine AdditionsNT4 Network Driver.vfd” and install the driver off of there.

N.B. If you configure a virtual machine with multiple network adapters – you should have them either disconnected or connected to different networks for this stage of the install.  Windows NT enables NETBIOS on all interfaces by default – so if you have two network adapters on the same network the installation will not accept any computer name you specify as it will say that there is a duplicate name on the network (i.e. the other network adapter).  Post installation you can go in and disable NETBIOS on specific controllers.

After network configuration the rest of the installation should proceed smoothly.  Once you are done with the operating system installation – the first thing you will need to do is to install Windows NT 4.0 Workstation Service Pack 6a (which needs to be loaded in order to install the Virtual Machine Additions).  This gets tricky as the version of Internet Explorer included with Windows NT 4.0 is not recent enough to be able to browse the Microsoft website.  So what I would recommend doing is to download the ‘network install’ of the service pack on the host operating system (the service pack can be downloaded from: and then use networking to transfer the file into the virtual machine for installation.  Alternatively you could use a program like WinISO ( to create an ISO image of the service pack installer and capture that inside of the virtual machine.

Once you have installed service pack 6a – you should then be able to install the Virtual Machine Additions (by selecting the option off of the Action menu).  The final thing that you should do is to install Internet Explorer 6 (download from on the host) and go to and install all the appropriate updates.