34-page PlayStation Forum thread.
Joystiq reader "Jim" wrote in to report the loss of 30 hours' worth of progress as a result of a glitch that the PS4 console identifies as "Error CE-34878-0." The bug isn't isolated to a specific game, as PlayStation community members report lost progress across several titles in the PlayStation 4's library, including NBA 2K14, Call of Duty: Ghosts, Battlefield 4, and Assassin's Creed 4: Black Flag. In rare cases, "CE-34878-0" prevents users from starting any PlayStation 4 application, rendering the console unusable.
PlayStation forum members suggest a variety of solutions to the issue, ranging from save file deletion to a full console replacement. We've reached out to Sony for comment and await a response.