Where is my Windows 8 Activation Key?

☠ MASQ ☠
Former digital concierge.
OEM Activation (OA v3.0) is the latest method by which Microsoft allow their OEM distributors to supply Windows 8.x and reduce the risk of piracy of their Windows product.

Unlike previous systems such as System Locked Pre-installation (SLP) which detected the manufacturer's hardware identity string in the systemboard BIOS the actual Product Key used to activate Windows is now injected into the BIOS by the manufacturer. A UEFI based BIOS has a reserved location - the ACPI Microsoft Data Management (MSDM) table - where the key is inserted by the manufacturer from a database of unique keys supplied from Microsoft.

The idea apparently is to make reinstallation easier for the end-user who now doesn't need to worry about losing that all important 25 character Product Key - if you have hardware which contains a valid Product Key then your copy of Windows will automatically activate. Try to install on the wrong hardware and you'll be out of luck.

It also means that Microsoft can stop worrying about printing any more of these:

I'm an animated GIF - open me to see a variety of Windows CoA Stickers[Windows CoA Stickers]

So don't panic when you can't find the Certificate of Authenticity (CoA) sticker on the case of your new Windows 8.x PC - It was never there and you don't need to know what the Product Key for activation is.

Or do you ....?

The lack of any tangible proof of authenticity other than a system that runs when you switch it on may not be an issue for your average home user but perhaps Microsoft & the OEMs didn't really look hard at the implications of the CoA's demise.

Most business users won't be supplying their users with OEM version of Windows on their new hardware but they will want to convert that OEM license into a credit for a volume licensing contract (reimaging rights) others still will want to take advantage of Microsoft's Downgrade Rights to move from Windows 8.x Pro to Windows 7

To do either - or even to fulfil a basis licensing audit - you need to supply evidence of your valid licence to use Windows 8.x to Microsoft

Imagine a conversation with Microsoft:

What evidence do Microsoft need?
please supply your Activation Key for Windows 8.x

Where is it?
It's in the code in the machine's BIOS!

Can I copy it from my CoA sticker?
No because (if your supplier is one of the big PC suppliers) you don't have one any more - you don't need to know the Key anyway - activation has been simplified

But you ask for my Key when I need to downgrade - don't you?
Ahhh.... Yes.... I'm just going to put you on hold while I talk to my supervisor ...

So for those of you who really do need to know what your Product Activation Key is for Windows 8.x

How to read the "hidden" key?

1) "The simple - keeps Microsoft happy - but not really reading the BIOS trick"

OEMs still put a Win 8 product Key in the registry - it's a "legacy thing" - it's not your actual activation Key from your BIOS (it's a generic OEM key tied to your manufacturer) but it will show Microsoft you have an OEM Windows 8 system and identifies the manufacturer to them. You can get it from any one of the numerous Key Finder utilities. I happen to like Nirsoft's offering ProduKey but Google will find you several good free utilities.

- the Key is unencrypted - decoded by your Key Finder

- Not the unique code from your system board
- Requires the Win8 install to be intact so if you've already downgraded you have to put everything back again just to get this info :(

Feeling adventurous ...

2) The tricky "Read the BIOS" and find your Key trick

You'd think that because people are going to need their Key to downgrade, Microsoft and the board manufacturer's would have made it easy to extract your unique key to prove your downgrade rights to Windows 7?


There are at least two tools available that will read the Key from the BIOS but neither will completely decrypt it.

These are:

Microsoft's OA3Tool - included as part of the Windows 8.1 ADK

RWEverything - a neat free (donations appreciated) little utility that lets you poke around your systems hardware addresses

Be aware that both these tools can write directly to hardware as well as read the contents. If you overwrite your OA3 key then your system board will no longer activate Windows 8.

The correct syntax for use of the use of the OA3Tool is:

>>oa3tool.exe /validate

Here is an example output:
OEM Activation Tool 3.0
                      (c) Copyright 2011 Microsoft Corp.
                      Version: 6.2.9200
                      The ACPI MSDM table:
                        4e 53 44 4d 55 00 00 00 03 e8 41 43 52 53 59 53
                        41 43 52 50 52 44 43 54 01 00 00 00 31 30 32 35
                        00 00 04 00 01 00 00 00 00 00 00 00 01 00 00 00
                        00 00 00 00 1d 00 00 00 42 48 33 52 4e 2d 42 37
                        46 44 4d 2d 33 3F 57 27 54 2d 34 43 52 34 58 2d
                        36 43 4b 38 4d
                      The ACPI MSDM data :
                        Signature:          MSDM
                        Length:            85 (0x55)
                        Revision:          3
                        CheckSum:          0xe8
                        OEMID:              ACRSYS
                        OEMTableID:        ACRPRDCT
                        OEMRevision:        0x1
                        CreatorID:          1025
                        CreatorRev:        262144
                      The ACPI MSDM table in hex:
                        01 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00
                        1d 00 00 00 42 48 33 52 4e 2d 42 37 46 44 4d 2d 
                        33 3F 57 27 54 2d 34 43 52 34 58 2d 36 43 4b 38 
                        4d  **
                      ACPI MSDM table payload:
                        Version:            1
                        Type:                1
                        DataLength:          29
                        Partial Product Key: 6CKHM
                      **This is not a real extract so don't try activating from it!!

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To convert the MSDM Key into something you can recognise convert the last 29 pairs from Hex to ASCII which should give you five blocks of five characters separated by 4 hyphens (2D in Hex) -  i.e. XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

It's really that simple :)

Upside - you get your actual unique activation key
Downside - Life really is too short!

Let's hope that either Microsoft of a third party come up with a more user friendly and less potentially risky tool to grab your system board's unique activation Key

Finally I could hardly write an OEM article without mentioning what happens if your system board dies.

As ever unless the board is replaced under warranty by the manufacturer (they will inject a new valid code into the replacement board and supply you with a windows 8 defective part key card (DPK) which contains the new code) then your licence to use Windows 8 is terminated. Unless you live in one of the European Union countries. But that is another story... :)

This article started as a suggested solution to a downgrading problem on Experts-Exchange
☠ MASQ ☠
Former digital concierge.

Comments (6)

I gave the Microsoft support my product key for 8.1 to downgrade to 7 and they said that doesn't help.  I requested a supervisor and they said the same thing.  Now that I look into more, it appears I need 8.1 Pro for me to downgrade...


And you did mention this.  My bad...
Distinguished Expert 2019

good article !
if MS sold their OS at 10$ instead of the current prices - they could retire their piracy  control servers, and everybody would be a lot happier
How can we ...convert the last 29 pairs from Hex to ASCII ?
Can you please show some idea ?
Most Valuable Expert 2023
Most Valuable Expert 2013


For example look at the output in the example table above.
Find where the output is "2D"
Find the same entry in your own output
Now find a Hex to ASCII conversion table
Here's an example http://www.asciitable.com/
Find "2D" under the Hex column and in the CHR column you'll find that's the equivalent of the hyphen "-" so those are the separators for the key.  
You convert the other Hex Codes the same way so:
"2D 41 42 43 44 45 2D" becomes  "-ABCDE-"

Does that help?

You could code this but for the few characters involved it doesn't take long to do it manually.
Hello MASQ,
thanks makes sense :)

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