Here’s what caused that massive Gmail outage

(Mark Lennihan / AP)

Google has responded to a widespread Gmail blackout Friday that disconnected as many as 42 million users for up to an hour. In a blog post, VP of Engineering Ben Traynor said that an internal software bug was behind the error.

"At 10:55 a.m. PST this morning, an internal system that generates configurations — essentially, information that tells other systems how to behave — encountered a software bug and generated an incorrect configuration," Traynor wrote. "The incorrect configuration was sent to live services over the next 15 minutes, caused users’ requests for their data to be ignored, and those services, in turn, generated errors."

The outage, Traynor continued, essentially fixed itself when the system responsible for the malfunction automatically generated the correct configuration and began propagating that throughout Google's live services.

Google offered an apology for the mishap and  vowed to improve its response time for future incidents.