US workspace messaging app Slack Technologies has today asked EU competition regulators to investigate Microsoft for allegedly abusing its market dominance.
Slack said the issue was Microsoft's Teams productivity software, which has seen a surge in demand as employees work remotely due to lockdowns aimed at slowing the spread of the coronavirus.
It said it has filed a complaint against Microsoft with the European Commission.
Teams competes with Slack and Zoom Video Communications both of which have also reported increased demand for video calling.
"Microsoft has 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 said in a statement.
Its general counsel David Schellhase accused Microsoft of reverting to past behaviour.
"They created a weak, copycat product and tied it to their dominant Office product, force installing it and blocking its removal, a carbon copy of their illegal behavior during the 'browser wars'," he said.
The European Commission, which has fined Microsoft a total €2.2 billion in a decade-long investigation involving tying cases and other practices, confirmed receipt of the complaint.
It said it would assess it under its standard procedures.