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Another Microsoft Migration Solution
Fresh from announcing their tenant-to-tenant migration “orchestrator” solution, message center notification MC1213779 (6 January 2026, Microsoft 365 roadmap item 485709) brings news of a new Slack to Teams migration solution. Microsoft’s new offering can move Slack public and private channels into Teams channels. The new tool is available in the Microsoft 365 admin center for targeted tenants with general availability worldwide due later this month.
Free and Easy
The big selling point is that Microsoft’s Slack to Teams migration solution is free. In a nutshell, the tool ingests export packages (ZIP files) generated by Slack and uploaded to Azure blob storage to populate Teams channels that the Slack channels are mapped to. Migration can be done for all or just selected Slack channels. Mapping is also required to allow the tool to resolve Slack usernames to Microsoft 365 accounts, and Microsoft has a PowerShell script to check Slack identities against Entra ID to find matching accounts.
Microsoft considers its Slack to Teams migration solution to be a preview offering until it reaches general availability. Some changes might take place between now and then, but it’s likely that the broad overview of the solution will remain the same. As always, take the time to read the online documentation to check the prerequisites (Azure is a big one), required permissions, and so on.
Microsoft’s Need for Migration Tools
Given the array of third-party migration tools that can move Slack content into Teams, many wonder why Microsoft needs its own solution. After all, although the software is free, it must be created, maintained, and supported, and all that activity costs.
The answer is that Microsoft wants to encourage customers to move off competing platforms. Although Teams is a dominant player for Microsoft 365 collaboration with over 320 million monthly active users (last official figure from October 2023), that still leaves 126 million of the 446 million paid Office 365 seats (data from October 2025) to play for. I assume that some of those 126 million users use Slack, and Microsoft would very much like to move them into the Teams ecosystem. Apart from anything else, migrated Slack users might buy Teams Premium and Teams Phone licenses.
It’s all about money. Microsoft wants to sell more licenses and can do so by migrating more people to its platform. Apart from anything else, the number of pure net new Microsoft 365 seats that Microsoft can sell is falling because of the size of the platform. This creates the need to use other methods to acquire new seats. According to DemandSage, Slack has 79 million monthly active users (December 2025), so it’s an attractive migration target.
The Third-Party Alternatives
A quick web search reveals that several ISV migration tools are available to move Slack content to Teams. Looking through the marketing material published by the different vendors, it seems that all the tools take roughly the same approach as used by Microsoft.
Discovering that tools don’t vary too much in how they approach migration isn’t surprising. Depending on available APIs, limited ways often exist to extract and ingest information, so the differences usually occur in how the extracted data is stored and processed prior to ingestion. However, marketing descriptions often hide technical reality, so I recommend that you test the available tools, including Microsoft’s new offering, before making a final choice.
So much change, all the time. It’s a challenge to stay abreast of all the updates Microsoft makes across the Microsoft 365 ecosystem. Subscribe to the Office 365 for IT Pros eBook to receive insights updated monthly into what happens within Microsoft 365, why it happens, and what new features and capabilities mean for your tenant.