Microsoft, the Department of Justice and others have thwarted the use of the Lumma Stealer malware that globally has infected nearly 400,000 computers.

The announcement was made at Microsoft’s Build developer conference on Monday, and was notable given Microsoft’s partnership with OpenAI. Musk founded xAI, the startup behind Grok, but he has also been locked in a feud with OpenAI since stepping down from its board in the late 2010s, citing disagreements over its leadership direction.