Hi @Brockton Roth ,
Welcome to Microsoft Q&A!
From looking at the GDK development downloads document, we can find:
Use of all files downloaded and installed from the downloads page is subject to the terms and conditions of the Xbox Game Development Kit Agreement between Microsoft Corporation or its affiliate, and you or your employer. If you or your employer doesn't have a valid Microsoft Game Development Kit (GDK) Agreement, you're not authorized to use these files.
If you have a valid GDK agreement, please directly contact the Xbox Support. Thanks for your understanding!
Sincerely,
Anna
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