An unusual bug on Facebook briefly labelled many people as dead.
The error on Friday caused the social network to show a memorial banner on user profiles for people who were still alive.
Users posted status updates to reassure friends and family they were not dead, despite Facebook's message.
"This was a terrible error that we have now fixed," a Facebook spokesperson said. "We are very sorry that this happened."
The message, intended for "memorialised profiles", erroneously appeared on the profile pages of a large number of users - including Facebook CEO Mark Zuckerberg.
"We hope people who love Mark will find comfort in the things others share to remember and celebrate his life," the banner on his page read.
Technology reporters and Facebook users, however, saw a humorous side to the story.
"Why Is Facebook Saying I'm Dead?" asked the New York Times' Katie Rogers. "At first, I was indignant. I was definitely not dead. Then I thought I had been hacked. Then I asked a few of my colleagues. Also dead."
"Facebook is capping one of the longest weeks in American history by telling everyone that they are dead," quipped The Verge, a technology website, in reference to the presidential election.
The memorial feature was introduced by Facebook in 2015 because of a number of high-profile cases where family wanted to access the social accounts of deceased loved ones.
User can opt to have their account turn into a memorial page upon their death, where Facebook contacts can leave message and share memories.
An alternative option is to have your account deleted after your death.