Windows Licensing Reference

A technical reference on Microsoft Volume Licensing, Windows and Office activation, and the Software Protection Platform — written for system administrators managing corporate Windows environments. Articles describe protocols, command-line tools, key types, and Microsoft licensing programs as they are documented by the vendor.

Scope. This site is a neutral, encyclopedic reference. It does not distribute software, product keys, or activation tools, and it does not offer purchasing advice. Each article cites the corresponding Microsoft Learn documentation.

Reference index

Activation Error Codes — 0xC004xxxx
Activation Troubleshooting — Diagnostic flow
Active Directory-Based Activation — AD-BA
Genuine Validation History — WGA → OGA → SPP
GVLK Keys — Generic Volume License Keys
HWID Digital License — Hardware binding
Key Management Service — KMS protocol
KMS Activation Renewal — 180-day cycle
KMS Host Configuration — Deploying a host
OSPP Command Reference — ospp.vbs
Product Key Types — Retail, OEM, MAK, GVLK
slmgr Command Reference — slmgr.vbs
Software Protection Platform — SPP / sppsvc
Volume Activation Methods — KMS, MAK, AD-BA, Token
Volume Licensing Programs — Open, EA, MPSA, CSP

About this reference

Microsoft Volume Licensing covers the agreements, product keys, and activation infrastructure used by organizations to license Windows and Office at scale. The articles collected here document the components of that system as they exist in current and historical Microsoft documentation, including the Key Management Service (KMS) protocol, the Software Protection Platform (SPP) service, the slmgr.vbs and ospp.vbs management scripts, and the published activation error codes.