Microsoft says it estimates that 8.5m computers around the world were disabled by the global IT outage.
It’s the first time a figure has been put on the incident and suggests it could be the worst cyber event in history.
The glitch came from a security company called CrowdStrike which sent out a corrupted software update to its huge number of customers.
Microsoft, which is helping customers recover said in a blog post: “We currently estimate that CrowdStrike’s update affected 8.5 million Windows devices.”
You can give up the key to user and force a replacement on next DC connection, but get people to enter a key that’s 32 characters long over the phone… Not automatable anyway.