The Commission is launching an investigation against Microsoft for purported anti-competitive practices related to its Teams software based on a complaint filed by Slack in 2020.

It is upset that Vole could bundle Teams with the Microsoft 365 suite of products, installing it on shedloads of machines while "hiding the true cost to enterprise customers." Slack wanted the regulator to force Microsoft to remove Teams from the Microsoft 365 suite and offer it separately at "fair" commercial prices.

At that time, Slack's Vice President of Communications and Policy Jonathan Prince was quoted as saying: “This is much bigger than Slack versus Microsoft – this is a proxy for two very different philosophies for the future of digital ecosystems, gateways versus gatekeepers.”

According to the report, the EC sent out a new set of questionnaires last month, which signifies that it's considering ramping up its investigation against Microsoft.

This is not the first time Slack and Microsoft have clashed. Vole considered acquiring Slack for $8 billion but ended up launching Teams. They have both been spending their time lobbing snark at each other.

Vole does not need another antitrust investigation as European regulators are already probing it over its $69 billion proposed acquisition of Activision Blizzard.