OEM Downgrade to Windows 7 Pro in a Virtual Machine



One of the biggest difficulties with regards to the use of Virtual Machines is obtaining the Windows license required to activate the Virtual Machine. Windows 7, Windows Vista and Windows XP have all Reached End of Retail and OEM sales so a new license cannot be purchased from Microsoft.

If you have bought a major OEM machine with a Windows 8.1 Pro OEM License or Windows 10 Pro OEM License your system has a SLIC version of 2.1 embedded in it’s UEFI BIOS. This may be used as an activation mechanism for Downgrade Rights to Windows 7 Pro (or Windows Vista Business) however these legacy OS will however lack the drivers for the new hardware and it will be impossible to install the OS and get it to run reliably in most cases (meaning downgrade rights by directly installing on the hardware is theoretical and of no practical use). This can be resolved by virtualising the Windows Installation with VMware and porting your OEM SLIC 2.1 from the host to the guest (which isn’t done by default).

Tutorial Video



There are different reasons for using a Virtual Machine. One of the reasons is just to run Legacy Software. If you have the setup files for your software you can copy then over to the VM and install your legacy software.

However life may not be so simple… The software used above is for a scientific instrument which has a serial port. I want to run Windows 7 64 Bit Bit on a Windows 10 64 Bit host and connect to the instrument using a Serial Port… Software may also be on a CD/DVD drive and may require the CD to be present in an optical drive to launch the setup. The software may also have a protection USB that needs to be connected to the VM in order for the software to launch. Finally a sister scientific instrument to the one above needs access to a Bootable Floppy Disc. I will first list some useful USB adaptors if you are trying to connect to legacy hardware.


If your software is on a CD/DVD you may however have an issue because the host PC you wish to virtualise your VM on does not have a CD/DVD drive. Firstly if you have an old computer with a CD/DVD drive then you should use WinImage to convert your CD/DVD to an ISO which can subsequently be loaded as a Virtual Drive in the VM. For more details see WinImage and Connecting to Legacy Hardware. If you do not have a CD/DVD drive then you’ll need a CD/DVD to USB one. I recommend the following (please use the affiliate links to help fund my guides).

Floppy Discs

You may have even older software… and require a floppy drive. Firstly if you have an old computer with the Floppy drive then you should use WinImage to convert your Floppy Discs to a FLP file which can subsequently be loaded as a Virtual Drive in the VM. For more details see WinImage and Connecting to Legacy Hardware. If you do not have a Floppy drive then you’ll need a USB one. The most highly rated virtual USB to floppy drive is the Esynic one. Note if you are needing a floppy drive to use as a boot drive. I recommend the following (please use the affiliate links to help fund my guides).

USB Ports

The next is if you are wanting to interface to some legacy hardware. If the hardware has a USB port, then most modern computers have USB ports and with VMware player you can readily connect to legacy devices over USB.

If your computer is brand new and only has USB Type-C connectors then you may need a USB Type C to USB adaptor. I used these on my XPS 13 9365 (please use the affiliate links to help fund my guides).

Serial Ports

For Serial Ports I’ve found the following by plugable to be the most useful and have tested them on several legacy scientific instruments in the lab. The following are affiliate links to Amazon.com and Amazon.co.uk. No driver is required for the Windows 10 Host by the Windows XP guest will require the driver listed here.

Checking for a SLIC

Systems which ship with the Pro Edition of Windows i.e. Windows 10 Pro OEM and Windows 8.1 Pro OEM have a System Licensed Internal Code SLIC version of 2.1:


I have a Dell OptiPlex 7060 with a Windows 10 Pro OEM Licence, I can press [Windows] and [ r ] and type in msinfo32 and press [Enter]:

I can see that it has an 8th generation i7 processor and is too new to install Windows 7 Pro OEM directly:

If I download RWEverything Portable and extract the folder:


I can then go to the Win 64 Folder:

Then the Portable folder:

Then launch the RW application:

ACPI Tables may already be open, if not select Access then ACPI tables:

In these tables, I see a MSDM which is for Windows 10 Product Activation and a SLIC which is for Windows 7 Pro Downgrade rights. It is Version 2.1 and is for Dell:

Windows 7 Installation Media

You need a Windows 7 Installation .iso for this. If you don’t have one see:

For Dell system’s the Dell Windows 7 Pro Skylake Reinstallation .iso is better as it is more up to date and will automatically apply Dell OEM SLP on a VM (which has the SLIC 2.1 ported from the Dell host).

Setting up the VM

I can then install and launch VMware Player:


I can then go ahead and create a new VM by selecting the Player Menu:

Then file and new vitual machine:

Do not load the .iso by default here, select I will install the operating system later:

Select Microsoft Windows 7 and Windows 7 64 Bit or 32 Bit depending on what architecture you are going to install. Select next:

You can leave the default Virtual Machine Name and Location if you want. I have changed both. Be sure to copy the location to your Windows 10 clipboard, then select next:

You can leave the default settings here or increase the size of the virtual drive and then select next:

Select customise hardware:

If you have plenty of RAM on your Host PC and a good processor you may wish to allocate more RAM to your VM and more processor cores:

Under New CD/DVD, select load ISO file and load your Windows 7 .iso:

Select Finish:

SLIC 2.1 Passthrough

Before loading Windows 7 on the VM navigate to the folder you saved the VM to and expand Type. Look for the VMware virtual machine configuration file:

Right click it, select open with notepad:

Add the following to the end of the VMware virtual machine configuration file and save.

acpi.passthru.slic = "TRUE"
acpi.passthru.slicvendor = "TRUE"
SMBIOS.reflecthost = "TRUE"

Then close notepad.

Install Windows 7

Open up VMware player and launch your Windows 7 VM:

VMware will also tell you the magic keyboard shortcut keys. [Ctrl] + [g] to take your mouse to the VM:

And [Ctrl] + [Alt] to take your mouse away from the VM.

Go ahead and install windows 7:

Select your language:

Select Install Now:

Accept the User License Agreement and select next:

Select Custom (advanced):

Select the virtual drive Disk 0 and select next:

Windows 7 will now install and restart the VM a few times (this does not restart the host):

Enter your user name and computer name:

Since your main Windows 10 Installation is likely password locked, it is not necessary to set a password here, select next:

If this screen shows (it won’t with Dell OEM Reinstallation .isos) uncheck Automatically Activate Windows when I’m online (it doesn’t matter if you check or uncheck this) and select Skip:

Select Use Recommended Settings:

Select your date and time:

You will not be on the Windows 7 Desktop:

Install VM Tools

Select Player → Manage → Install VMware tools:

Accept the User Account Control Prompt and then select Yes:

Select Next:

Next again:

Then Install:

Then Finish:

Then select yes to restart the VM (the host won’t restart):

You can now resize your VM as desired and drag and drop to it like a normal window:

Applying OEM System Locked Preinstallation

Select start and right click the computer and select properties:

Check the activation status, if using a Dell OEM Reinstallation .iso and a Dell SLIC 2.1, Windows 7 Pro should already be activated. In this case I am using a Microsoft generic .iso that doesn’t apply OEM SLP automatically (this will be the case for Lenovo and HP systems):

I have put together the OEM Cert Collection along with an associated 2 line script to install the Cert and Apply the associated OEM SLP Key. After Installation copy the OEM folder containing the cert and OEM SLP key to your C:\ Drive and then run the script file.

It is available as a .zip file here:


Copy the OEM SLP collection over to your VM:

Open your OEM’s folder in this case, Dell:

Open 7 Professional:

Select the OEM folder:

Copy it to the C:\ Drive

In the C:\ Drive open the OEM folder:

You should have a slp file and a OEM Digital License:

Right click the slp.cmd script and select Run as Administrator:

Accept the User Account Control Prompt:

Select OK when told the license is installed:

Select OK when the Product Key is installed successfully. The Product Key here is generic or all Dell Windows 7 Pro OEM Licenses but will differ depending on the OEM you selected:

Right click the start button and select Properties:

Windows 7 Pro has now activated on your virtual machine using your host’s SLIC 2.1:

If you have a Windows is not activated window open RWEverything in your VM and check the SLIC 2.1 is present. If it is not, your configuration file isn’t right and you should close down the VM and try to alter it, then try the OEM SLP activation again:

Updating Windows 7

Windows 7 Installation Media is from 2011 and over 5 years out of date (Dell Windows 7 Reinstallation Media is from 2016 and 3 years out of date). You are best to use the following standalone updates:

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