Part 5 of a sourced series. Every fact links to its source — regulator-quoting reporting, the parties' own statements, and law-firm analysis. Accusations are labeled as allegations and attributed to who made them. Nothing here says Microsoft broke the law; no regulator found that, and the case closed without one. My opinions are marked. Corrections policy at the bottom; an evidence explorer lets you check every claim.
A chat app that came whether you wanted it or not
For years, if you bought Microsoft's Office suite, Teams came with it. Pre-installed. Hard to remove. And, a rival argued, quietly subsidized by the thing you actually came to buy.
That rival was Slack — and in 2020 it decided to make its grievance a legal one.
To be clear up front: what follows is a five-year arc of a complaint, an investigation, a preliminary charge, and a settlement — not a verdict. The case ended without anyone being found to have broken the law.
The complaint (2020)
On 22 July 2020, Slack Technologies filed a competition complaint against Microsoft with the European Commission. Slack accused Microsoft of illegally tying Teams to its dominant Office suite, force-installing it for millions, blocking its removal, and hiding the true cost to enterprise customers (Slack; Quinn Emanuel).
In Slack's own words, Microsoft had "illegally tied its Teams product into its market-dominant Office productivity suite, force installing it for millions, blocking its removal, and hiding the true cost to enterprise customers" (Slack).
Those are Slack's words and Slack's allegations — not findings, and not mine.
The investigation (2023)
For three years, not much moved in public. Then, on 27 July 2023, the European Commission opened a formal antitrust investigation — case AT.40721 — into whether Microsoft abused a dominant position by tying Teams to Office 365 and Microsoft 365, and by limiting interoperability with rival communication tools (European Commission; SiliconANGLE).
Opening proceedings is the start of an inquiry, not the end of one. It says the regulator has questions — not that it has answers.
The first fix (2023)
Microsoft moved before it was charged. Effective 1 October 2023, it unbundled Teams from Microsoft 365 and Office 365 across the European Economic Area and Switzerland — selling the suites without Teams at a lower price (about €2/month less) and offering Teams as a standalone product (Microsoft).
This was Microsoft's own voluntary change, and Microsoft framed it as addressing the Commission's concerns. The Commission would later disagree that it went far enough.
The preliminary charge (2024)
On 25 June 2024, the Commission sent Microsoft a Statement of Objections — setting out its preliminary view that Microsoft had breached Article 102 TFEU by tying Teams to its business suites. The Commission stressed the step does not prejudge the outcome (European Commission; TechCrunch).
This is the boundary that matters, so read it slowly. A Statement of Objections is a preliminary charge, not a ruling. As TechCrunch put it at the time: "No final decision or fines have been imposed" (TechCrunch).
And in that preliminary assessment, the Commission's view was that Microsoft's 2023 unbundling was not enough — that further changes were necessary to restore competition (TechCrunch). The first fix, in the regulator's preliminary telling, needed to go further.
The second fix (2025)
So Microsoft came back with more. In May 2025, it proposed revised commitments: offering the suites without Teams at an appreciably lower price, giving customers recurring chances to switch, building interoperability for competing tools, and letting customers export their Teams data. The Commission opened those commitments to a market test (Microsoft; Slaughter and May).
Microsoft's framing of its own offer was confident — it said the commitments "represent a clear and complete resolution to the concerns raised by our competitors" (Microsoft). That's Microsoft's characterization of its own proposal.
The ending (2025) — binding, but no fine
On 12 September 2025, the Commission accepted Microsoft's commitments and made them legally binding under Article 9 of Regulation 1/2003 (TechCrunch; Loyens & Loeff).
Here is the legal punchline, and it cuts both ways. An Article 9 decision, by design, resolves a case without any finding or admission that Microsoft infringed EU law — and without a fine. As Loyens & Loeff explain, Article 9 "allows the Commission to make commitments legally binding without formally concluding whether an infringement occurred" (Loyens & Loeff).
What Microsoft is now bound to do is real: the commitments run seven years, and the interoperability and data-portability obligations last ten years, overseen by a monitoring trustee (TechCrunch; Loyens & Loeff). The Commission's competition chief, Teresa Ribera, said the decision makes binding "for seven years or more Microsoft's commitments to put an end to its tying practices" (TechCrunch).
Then the complaints fell away. Following the market test, both complainants — Slack (owned by Salesforce) and alfaview — withdrew their complaints against Microsoft (CNBC). A withdrawal is not an admission of wrongdoing by anyone; it is the parties stepping back.
Microsoft's side
Microsoft did not treat this as a loss, and in fairness, the legal record supports its framing. The company said it is "pleased to have resolved this matter," and characterized its commitments as a "clear and complete resolution" to competitor concerns (Microsoft). No infringement was found. No fine was paid.
My read
Opinion — Michael. I'm not telling you Microsoft broke the law. The Commission never found that, the case closed without a finding, and there was no fine — so neither will I. What I keep turning over is the shape of it: five years, two rounds of fixes, a binding ten-year leash on interoperability — and the trigger was simply a chat app riding in on a product you'd already decided to buy. You don't need a villain for default-installed software to bend a market; you just need the bundle to be the path of least resistance. The tell, for me, is that the first fix wasn't enough and the second one runs a decade. That's not the language of a non-issue. Bad systems, not bad people — and a commitments file that will be quietly enforced long after the headlines move on.
You don't have to take my read. The complaint, the Statement of Objections, Microsoft's own announcements, and the law-firm breakdowns of the Article 9 decision are all linked above — judge them yourself.
Sourcing & corrections
Slack's complaint is drawn from Slack's and Quinn Emanuel's own releases; the investigation, Statement of Objections, and final decision from the European Commission, corroborated by TechCrunch, SiliconANGLE, CNBC, Slaughter and May, and Loyens & Loeff; Microsoft's unbundling steps, proposed commitments, and response from Microsoft's own statements — each linked inline and matched in the explorer. The Article 9 framing — binding commitments with no finding of infringement and no fine — is the legal core of this piece and is sourced to the regulator-quoting reporting and law-firm analysis above. Spot an error or something unfair? Email mpolzin@zimzap.com or message me on LinkedIn — I'll review and correct.
Next — Part 6: "The VMware Shock."
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