Facebook users had to keep their status updates to themselves this week when the world’s most popular social networking site screeched to a halt for two-and-a-half hours. It’s the worst outage Facebook has seen in four years and marked the second bout of downtime in as many days for Facebook, which was previously hit with a minor outage because of an “issue with a third-party provider.”

“The key flaw that caused this outage to be so severe was an unfortunate handling of an error condition," said Robert Johnson, Facebook’s director of software engineering, in a blog post. He explained that software designed to detect and fix such errors backfired, compounding the original problem. “An automated system for verifying configuration values ended up causing much more damage than it fixed,” he said.

“The intent of the automated system is to check for configuration values that are invalid in the cache and replace them with updated values form the persistent store,” Johnson continued. “This works well for a transient problem with the cache, but it doesn’t work when the persistent store is invalid,” he said.

The outages coincide with the much-anticipated Oct. 1 release of “The Social Network,” a film dramatizing Facebook’s transformation from a Harvard campus fad to a global phenomenon boasting more than 500 million members, up from 300 million in September of last year.

Despite online reports that Facebook’s founder Mark Zuckerberg attended a screening of the film in Seattle, he’s unlikely to start a movie fan club. Officially, Facebook said in a brief prepared statement that “the story presented in ‘The Social Network’ doesn’t match reality. It’s a portrayal designed to lure people into movie theaters rather than tell an accurate story.” And in an interview with ABC’s Diane Sawyer in July, Zuckerberg said, “I mean, the real story is actually probably pretty boring, right? I mean, we just sat at our computers for six years and coded.”