Slack to Microsoft Teams Migration

No, and we would rather you hear that from us than discover it on cutover day. At the time of writing it migrates channel content: public and private channels, channel messages including threads and standard reactions, channel file attachments, canvases and lists (as file attachments), and channel membership. It does not migrate direct messages, group chats, Slack workflows or custom app integrations. For most organizations, channels are where the durable knowledge lives, so the native tool covers the bulk of the value at no license cost; the gaps are handled by decision — third-party tool, read-only Slack period, or deliberate retirement — not by surprise.

Sometimes, and it takes three things: a Slack plan that permits exporting them (Business+ or Enterprise Grid — Free and Pro export public channels only), Slack's approval of the extended export, which it grants on a stated legal basis, and a third-party migration tool, because the native tool does not carry direct messages. That adds cost and time, and direct messages are personal by nature. Our honest experience is that many organizations choose a defined read-only Slack period instead, so people can look things up while the habit fades. We put both options, with costs, in front of you in the design workshop.

Any plan can export public channel history. Free workspaces are limited to recent history, so what exists to export may be less than what was posted. Private channels and direct messages require Business+ or Enterprise Grid plus an application to Slack for the extended export — Enterprise Grid additionally exposes the Discovery API that third-party tools use. We confirm your position in week one, because an export limitation found late is the single most common reason a Slack migration slips.

Messages arrive under the Microsoft 365 account each Slack member is mapped to, which is why identity mapping is a deliverable rather than a checkbox — Microsoft provides a script to match Slack identities against Entra ID, and the tool accepts CSV mappings for scale. Accounts that cannot be mapped (departed staff, contractors, bots) need a decision before the run: map them to a designated account, or accept the placeholder attribution the tool applies. We record that decision, and the pilot verification shows you exactly how it looks before the production waves.

Channel file attachments migrate with their messages and land in the Teams channel's SharePoint document library, so they open from the conversation the way they did in Slack. Two practical cautions: the files are retrieved during the run, which is why the Slack workspace stays active until verification is complete, and file volume is one of the factors we size in the quote. Files that were only ever in direct messages follow the direct-message decision.

Almost never, and it should not. A Slack workspace with a few hundred channels copied into one team is unusable and runs into Microsoft's per-team channel limits, especially for private channels. The design workshop groups channels into teams by department or function, archives stale channels at the source instead of migrating them, and places private and shared channels deliberately. Migrating less, on purpose, is how Teams ends up cleaner than the Slack it replaces.

They are inventoried with an owner and a recommendation for each: many common integrations have a native Teams app or connector, Workflow Builder automations often map to Power Automate templates, and some are simply abandoned experiments nobody will miss. What has to be rebuilt — a custom Slack app, a complex multi-step workflow — is separate development work we scope through Custom Microsoft Teams App Development, with the inventory as the brief.

No. Slack and Teams coexist through the whole engagement; the migration reads from Slack and writes into Teams while both keep working. Cutover is a date, announced in advance, on which Slack switches to read-only rather than dark: people can still look things up, and read-only Slack is the rollback path in the days around cutover. The user-visible change is where new conversations happen, and the adoption kit exists to make that change land.

After verification is complete, the read-only period you chose has run, retention exports are taken, and integrations that still point at Slack are rehomed — all of which is the decommission checklist. Cancelling before the migration is verified removes your rollback path and can remove access to files that have not yet been retrieved, so the checklist sequences it. Contract timing is yours to negotiate; we tell you when the technical conditions are met.

$12 per user plus a $2,500 tenant fee, as an estimate that becomes a fixed written quote before work begins — you pay after you approve delivery. The tenant fee covers the inventory, the design workshop, the native-tool migration setup, the governance baseline and the adoption kit; the per-user component scales with the Slack members mapped into the migration. Direct-message scope via a third-party tool, multiple workspaces or Enterprise Grid organizations, and unusually large file volumes are priced in the quote rather than discovered mid-project.

Only if it lands ungoverned, which is why the governance baseline is part of the cutover, not a follow-up: a naming convention, an expiration policy that asks owners to renew, guest-access settings and a deliberate team-creation model are active before users arrive. The migration itself archives stale channels at the source instead of copying them. If your existing Teams estate already has sprawl — ownerless teams, forgotten guests — the deeper lifecycle implementation is our Microsoft Teams Governance and Sprawl Cleanup, and the two pair well.

The design workshop starts from your current Teams estate, not from a blank tenant. Where a Slack channel has an obvious existing home, it is mapped into that team; where it does not, a new team is created under the naming convention. Nothing in the existing estate is deleted or restructured by this engagement, and channel owners verify their migrated content before it goes live for everyone.