The file ToolkitDocumentation-x86_en-us.msi is a component of the Windows Assessment and Deployment Kit (ADK). It contains the local offline documentation for the various tools included in the kit, such as the Application Compatibility Toolkit (ACT) and the User State Migration Tool (USMT). Download Information
Specify a Path: Choose a local folder. The installer will download all components, including the Installers subfolder where the .msi and .cab files are stored. adk toolkit documentationx86enusmsi download link
Then point ADKSOURCE to that folder.
For the most reliable and secure installation, it is recommended to use the official Microsoft ADK Download Page. Windows 11 ADK (Latest Versions): ADK 10.1.28000.1 (November 2025) ADK 10.1.26100.2454 (December 2024) Historical Component Link: The file ToolkitDocumentation-x86_en-us