The longstanding debate between Microsoft and Slack takes a new turn as Salesforce files a lawsuit against Microsoft in London’s High Court. This legal battle centers on allegations that Microsoft unfairly bundled its Teams application with the Microsoft 365 suite, potentially locking out competition. A Slack spokesperson commented, “Microsoft’s practices harmed competition, using tying and bundling of Teams to limit customer choice.” Microsoft, however, dismissed the claims by attributing Slack’s challenges to its own product limitations, unrelated to Microsoft’s actions.
Similar accusations arose in 2020 when Slack filed a complaint with the European Commission, accusing Microsoft of using its Office suite’s reach to force Teams adoption. This resulted in a settlement in September 2025, mandating a price differentiation between plans with and without Teams, thereby addressing competition concerns. Despite the settlement, Microsoft swiftly reintroduced Teams-bundled packages and adjusted pricing, prompting Slack to challenge the perceived adequacy of these actions.
In the UK, this wasn’t the only legal action Microsoft faced. The Competition Appeal Tribunal is pursuing a class action representing nearly 60,000 British businesses. This action alleges Microsoft overcharged for Windows Server licenses, favoring its own Azure platform over competitors like AWS and Google Cloud. The claim could result in damages of up to £2.1 billion.
Simultaneously, the UK’s Competition and Markets Authority has initiated an investigation into Microsoft’s cloud licensing tactics, examining whether these practices disadvantage competitors. Microsoft disputes these charges but cannot ignore the cumulative scrutiny and potential impact on their business strategies.
For enterprise tech buyers, the implications of this lawsuit are not immediate. Legal proceedings may extend over several years, and any potential adjustments by Microsoft could emerge gradually and vary by region. However, organizations renewing Microsoft Enterprise Agreements should now consider the documented pricing differentials for licensing tiers and possibly negotiate for Teams-excluded pricing in line with European precedents.
Overall, these events are part of a larger pattern of regulatory examination across Microsoft’s cloud, AI, and security offerings. While not cause for immediate concern, businesses should factor these elements into their long-term strategy to mitigate potential vendor dependency risks. For enterprises, this ongoing saga signifies the importance of staying informed and agile in decision-making concerning technology partnerships and strategies.
