Facebook explains the cause behind its early Thursday downtime

On Thursday morning at approximately 1 a.m. PT, Facebook (s fb) experienced a rare occurrence: it shut down. For roughly half an hour, users across the world couldn’t access the Facebook site or app. Later on Thursday revealed what triggered the brief, rare outage — a hiccup in software:

Late last night, we ran into an issue while updating the configuration of one of our software systems. Not long after we made the change, some people started to have trouble accessing Facebook. We quickly spotted and fixed the problem, and in less than 30 minutes Facebook was back to 100% for everyone. This doesn’t happen often, but when it does we make sure we learn from the experience so we can make Facebook that much more reliable. Nothing is more important to us than making sure Facebook is there when people need it, and we apologize to anyone who may have had trouble connecting last night.

This outage was the longest since April 2010, when the company’s platform and all social plug-ins went out for 2.5 hours.