Microsoft GCC High

    Microsoft GCC High Migration for Ohio Defense Suppliers

    Short answer

    Microsoft 365 GCC High is Microsoft's US government cloud for defense contractors that handle DoD CUI or ITAR-controlled data. Moving to it is not an upgrade of your current tenant: Microsoft validates your eligibility, a brand new GCC High tenant is created, and mailboxes, OneDrive, SharePoint and Teams data are copied across with migration tooling before a planned cutover. For Ohio manufacturers with export-controlled drawings or DoD CUI, it is usually the cleanest way to give the enclave a defensible CMMC boundary.

    Who actually needs GCC High

    Microsoft positions GCC High for US defense contractors that hold DoD Controlled Unclassified Information or data subject to ITAR. It is assessed against NIST SP 800-53 at the FIPS 199 High baseline, is designed to DoD Cloud Computing SRG Impact Level 4 controls, and is supported by Microsoft's DFARS 252.204-7012 commitments. If you do not handle export-controlled data, Microsoft 365 GCC or a scoped CUI enclave may be enough. Scoping decides, which is why we start with a gap assessment.

    How a GCC High migration works

    1. Scope and decide. Confirm which users, data and workflows touch CUI or ITAR data. Many Ohio suppliers move only engineering, quality and program staff into GCC High and keep everyone else in commercial Microsoft 365.
    2. Eligibility validation. GCC High is sold through Volume Licensing and authorized partners after Microsoft validates eligibility. Expect to show evidence of a DoD contract or sponsorship involving controlled data and your CAGE code or SAM registration. Trials are not available.
    3. Build the new tenant. Identity (Entra ID), MFA and Conditional Access, Intune device compliance, DLP and sensitivity labels, audit logging and FIPS-validated encryption are configured before any data moves.
    4. Migrate data. Microsoft does not support in-place conversion or cross-tenant sync between commercial and government clouds, so mail, files and Teams content are copied with third-party migration tools in staged passes.
    5. Cut over. DNS and mail flow switch, devices are re-enrolled, and users get new sign-ins. Plan around production schedules and ERP or MES integrations.
    6. Document for CMMC. Capture the configuration as SSP evidence and map inherited controls using Microsoft's shared responsibility documentation.

    Things that surprise people

    • GCC High users can share and collaborate natively only with other GCC High organizations, so outside collaboration needs a plan.
    • Some commercial features are missing or different. For example, Viva Engage is not available and Teams Phone uses Direct Routing.
    • Microsoft support for GCC High is outside the accreditation boundary, so never paste CUI into a support ticket.
    • Third-party apps and integrations must be re-validated against the government cloud endpoints.

    How TRNSFRM helps

    TRNSFRM scopes, builds and migrates GCC High environments for Ohio defense suppliers and then manages them day to day as part of compliance-driven managed IT. See how we handled a manufacturer's CMMC, GCC High and ERP cutover.

    Book a free CMMC gap audit

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    Frequently Asked Questions

    Related

    Microsoft GCC & GCC High

    Which government cloud fits CMMC and ITAR.

    Case Study: CMMC, GCC High and ERP Cutover

    How a manufacturer made the move.

    ITAR Compliance

    Export-controlled data handling.

    CMMC Compliance Services

    Gap assessment, remediation and readiness.

    Defense & DoD Suppliers

    How we work with the defense supply chain.

    CMMC Gap Assessment Cost (Ohio)

    Process and DoD cost estimates.

    Free Ohio CMMC Gap Audit

    A free 45-minute readiness gap audit.

    Sources

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