https://www.theverge.com/2018/4/6/17203114/facebook-mark-zuckerberg-messages-deleted-messenger-inbox

Facebook has admitted the company has been secretly deleting messages sent on Messenger by founder and CEO Mark Zuckerberg. “After Sony Pictures’ emails were hacked in 2014 we made a number of changes to protect our executives’ communications,” says a Facebook spokesperson in a statement to TechCrunch. “These included limiting the retention period for Mark’s messages in Messenger. We did so in full compliance with our legal obligations to preserve messages.”

Old Facebook messages sent by Zuckerberg have simply vanished in some existing threads, and TechCrunch reports that affected messages no longer appear in Facebook’s download your information tool. Recent messages from Zuckerberg reportedly remain in some users’ inboxes, and the company doesn’t appear to have cleared out all of Zuckerberg’s older messages prior to 2014. Facebook has never publicly disclosed the removal of these messages until now, and simply quietly deleted them from recipient’s Messenger inboxes. Regular Facebook users aren’t able to delete their own messages from other people’s Messenger inbox, and a special process was applied to Facebook executives.