PlayStation 3 users around the world have been left unable to connect to the PlayStation Network, with Sony still unable to identify the source of the problem.
Players of the online service - which allows its 38 million users to connect to online stores, download software and play multiplayer games - started reporting difficulties yesterday afternoon.
The problem is also affecting players of single-player, trophy-based games such as Heavy Rain and BioShock 2, as these require trophy information to be synchronised with Sony's online servers.
Players get an error message reading, "Registration of the trophy information could not be completed. The game will quit. (8001050F)"
Some users have even lost their precious trophies.
"We're aware that many of you are having problems connecting to PSN, and yes, we're looking into it. Stay tuned for updates," the company said in its Twitter channel.
"Readers/followers are confirming that 'slim' units (120/250 GB models) are connecting normally."
"Know that we have narrowed down the issue and have engineers working to restore service even as you read this," promises the company's social media manager Jeff Rubenstein. "We apologize for any inconvenience this may cause you, and genuinely appreciate your patience while we work to resolve this."
Some players have suggested that the problem is linked to a Y2K-style clock issue, but reported that resetting the clock doesn't help. The problem might just fix itself later today as mysteriously as it began.