SharePoint Migration Tool (SPMT) download returns ContainerNotFound / 404 (0x08000301) and installed copy won't open

The matching ContainerNotFound and HTTP 404 failures across the official links, bootstrap installer, and an existing installation indicate a current Microsoft-hosted SPMT installer-resource incident; check Microsoft 365 Service health and report the incident rather than repeatedly reinstalling or repairing Windows.

Current status and download link

As of November 2, 2026, a current Microsoft Q&A report documents the same SPMT/Migration Manager installer-resource failure. It identifies ContainerNotFound, HTTP 404, and 0x08000301 as a download/build-retrieval problem and recommends checking Service health and opening a support case when the official paths remain unavailable.^1^

Microsoft’s documentation still designates these as the current installation links:

• GA/First Release: https://aka.ms/spmt-ga-page
• Public Preview: https://aka.ms/spmt-beta-page

Both are listed on the canonical installation page.^2^ The current release notes also identify [IP Address] as the latest GA and preview build and point to those same links.^3^

Therefore:

• The documented location has not moved.
• There is currently no independently documented working replacement URL.
• The preview is not a workaround while its Microsoft-hosted container also returns 404.

Report the outage

1. In the Microsoft 365 admin center, open Health → Service health.
2. Look for a SharePoint Online or migration-related advisory.
3. If no relevant incident appears, use Report an issue from Service health or open Support → New service request.^4^

Include:

• ContainerNotFound and 0x08000301
• The failing GA and preview URLs
• UTC timestamp and Request ID
• Confirmation that the failure occurs with a colleague’s setup and an existing installation
• Results from another network, if available

Service health is tenant-specific and is the primary incident channel; the public service-status page is the fallback if the admin center itself is unavailable.^5^

Retirement and Migration Manager

SPMT is not documented as retired. Microsoft still publishes current SPMT release notes and describes it as the supported downloadable tool for file-share and SharePoint Server migration.^6^

Migration Manager is an alternative only for supported sources:

• File share source: Migration Manager is a suitable alternative. Open the SharePoint admin center → Migration Center → File shares, install an agent, and create the migration task there.^7^
• SharePoint Server source: Migration Manager does not support SharePoint Server content; Microsoft directs that scenario to SPMT.^8^

Offline installer and existing installation

Microsoft’s current SPMT installation documentation provides bootstrap/web installation links but does not document a standalone offline installer. A setup executable copied from another computer still needs to retrieve remote builds, matching the 404 shown during Preparing.

Likewise, an installed copy can depend on its online deployment/update location. ClickOnce deployments can check a web update location at launch, so a broken publishing endpoint can prevent startup.^9^

Do not manually copy or modify installer/cache directories. Wait for Microsoft to restore the endpoint, then:

1. Launch the existing installation again.
2. If it remains broken, uninstall SPMT from Settings → Apps → Installed apps.
3. Reinstall from the canonical GA page.
4. Only if installation still fails after the URLs return normally, verify x64 Windows, .NET Framework 4.6.2 or later, and the x64 Visual C++ Redistributable as documented in Microsoft’s installation troubleshooting guidance.^10^

References

1. Can not install SPMT (share point migration tool)
2. Step 1: Install the SharePoint Migration Tool (SPMT)
3. Release Notes: SharePoint Migration Tool (SPMT)
4. How to check Microsoft 365 service health
5. Microsoft 365, Dynamics 365 & Power Platform incident readiness for Microsoft Engage Center
6. Overview of the SharePoint Migration Tool (SPMT)
7. Overview: Migrate your file shares to Microsoft 365
8. Frequently Asked Questions: Migration Manager File Share
9. ClickOnce deployment and security
10. Troubleshooting SPMT installation issues