Extracting Windows 10 license keys from machines

You can use NirSoft's 'ProduKey'. You can download it on nirsoft.net. This is a freeware utility which allows you not only to see Windows keys, but also various other Microsoft product keys.

This method works for volume licenses, as well as for OEM and other standalone licenses.

Note that it does not officially support Windows 10, but my experience so far has been successful.

Enter:

wmic path softwareLicensingService get OA3xOriginalProductKey 

into Command Prompt (Admin), then hit enter.

This will show the original Windows 10 product key for each machine.

NOTE: This only works for OEM licenses.

If you are running windows on a genuine windows copy that is connected to the motherboard (an OEM key), you can use this command i windows administrator command prompt:

wmic path softwareLicensingService get OA3xOriginalProductKey

or in Administrator Powershell

$(Get-WmiObject -query 'select * from SoftwareLicensingService').OA3xOriginalProductKey

however, if you entered a product key or have a digital liscence connected to the computer, this won't work. You can get the product key that is on your computer with a VBScript as shown here authored by Hackoo. There are many different VBScripts well known to get your product key and most of them are based on the registry since the registry stores your product key formatted in a specific way (semi-encrypted but not really if you will).

Sometimes, the registry values change or get removed so in that case, I would use extra third-party software if that is not a limitation or of concern. My favorite right now is ProduKey

_{VBScript by Hackoo below}

const HKEY_LOCAL_MACHINE = &H80000002

strKeyPath = "SOFTWARE\Microsoft\Windows NT\CurrentVersion"
strValueName = "DigitalProductId"
strComputer = "."
dim iValues()

Set oReg = GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & _ 
  strComputer & "\root\default:StdRegProv")
oReg.GetBinaryValue HKEY_LOCAL_MACHINE,strKeyPath,strValueName,iValues

Dim arrDPID
arrDPID = Array()
For i = 52 to 66
  ReDim Preserve arrDPID( UBound(arrDPID) + 1 )
  arrDPID( UBound(arrDPID) ) = iValues(i)
Next
' <--- Create an array to hold the valid characters for a microsoft Product Key --->
Dim arrChars
arrChars = Array("B","C","D","F","G","H","J","K","M","P","Q","R","T","V","W","X","Y","2","3","4","6","7","8","9")

' <--- The clever bit !!! (Decrypt the base24 encoded binary data) --->
For i = 24 To 0 Step -1
  k = 0
  For j = 14 To 0 Step -1
    k = k * 256 Xor arrDPID(j)
    arrDPID(j) = Int(k / 24)
    k = k Mod 24
  Next
  strProductKey = arrChars(k) & strProductKey
  ' <--- add the "-" between the groups of 5 Char --->
  If i Mod 5 = 0 And i <> 0 Then strProductKey = "-" & strProductKey
Next
strFinalKey = strProductKey

' <--- This part of the script displays operating system Information and the license Key --->
strComputer = "."
Set objWMIService = GetObject("winmgmts:" _
  & "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")
Set colOperatingSystems = objWMIService.ExecQuery _
  ("Select * from Win32_OperatingSystem")
For Each objOperatingSystem in colOperatingSystems
  strOS   = objOperatingSystem.Caption
  strBuild   = objOperatingSystem.BuildNumber
  strSerial   = objOperatingSystem.SerialNumber
  strRegistered  = objOperatingSystem.RegisteredUser
Next

Set wshShell=CreateObject("wscript.shell")
strPopupMsg = strOS & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Build Number:  " & strBuild & vbNewLine
strPopupMsg = strPopupMsg & "PID:  " & strSerial & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Registered to:  " & strRegistered & vbNewLine & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Your Windows Product Key is:" & vbNewLine & vbNewLine & strFinalKey
strPopupTitle = "Microsoft Windows License Information"
wshShell.Popup strPopupMsg,,strPopupTitle,vbCancelOnly+vbinformation

_{Another VBScript that works}

Option Explicit
Dim objshell,path,DigitalID, Result
Set objshell = CreateObject("WScript.Shell")
'Set registry key path
Path = "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\"
'Registry key value
DigitalID = objshell.RegRead(Path & "DigitalProductId")
Dim ProductName,ProductID,ProductKey,ProductData
'Get ProductName, ProductID, ProductKey
ProductName = "Product Name: " & objshell.RegRead(Path & "ProductName")
ProductID = "Product ID: " & objshell.RegRead(Path & "ProductID")
ProductKey = "Installed Key: " & ConvertToKey(DigitalID)
ProductData = ProductName & vbNewLine & ProductID & vbNewLine & ProductKey
'Show messbox if save to a file
If vbYes = MsgBox(ProductData & vblf & vblf & "Save to a file?", vbYesNo + vbQuestion, "BackUp Windows Key Information") then
Save ProductData
End If
'Convert binary to chars
Function ConvertToKey(Key)
Const KeyOffset = 52
Dim isWin8, Maps, i, j, Current, KeyOutput, Last, keypart1, insert
'Check if OS is Windows 8
isWin8 = (Key(66) \ 6) And 1
Key(66) = (Key(66) And &HF7) Or ((isWin8 And 2) * 4)
i = 24
Maps = "BCDFGHJKMPQRTVWXY2346789"
Do
Current= 0
j = 14
Do
Current = Current* 256
Current = Key(j + KeyOffset) + Current
Key(j + KeyOffset) = (Current \ 24)
Current=Current Mod 24
j = j -1
Loop While j >= 0
i = i -1
KeyOutput = Mid(Maps,Current+ 1, 1) & KeyOutput
Last = Current
Loop While i >= 0

If (isWin8 = 1) Then
keypart1 = Mid(KeyOutput, 2, Last)
insert = "N"
KeyOutput = Replace(KeyOutput, keypart1, keypart1 & insert, 2, 1, 0)
If Last = 0 Then KeyOutput = insert & KeyOutput
End If
ConvertToKey = Mid(KeyOutput, 1, 5) & "-" & Mid(KeyOutput, 6, 5) & "-" & Mid(KeyOutput, 11, 5) & "-" & Mid(KeyOutput, 16, 5) & "-" & Mid(KeyOutput, 21, 5)
End Function
'Save data to a file
Function Save(Data)
Dim fso, fName, txt,objshell,UserName
Set objshell = CreateObject("wscript.shell")
'Get current user name
UserName = objshell.ExpandEnvironmentStrings("%UserName%")
'Create a text file on desktop
fName = "C:\Users\" & UserName & "\Desktop\WindowsKeyInfo.txt"
Set fso = CreateObject("Scripting.FileSystemObject")
Set txt = fso.CreateTextFile(fName)
txt.Writeline Data
txt.Close
End Function