Sony has retracted the 4.45 PS3 firmware update, following reports that the software has been bricking consoles. The download has been removed from the publisher's website, and you are advised not to update your PS3 until further notice.
The update was designed to tweak a number of hardware features - including giving you the option to disable trophy notifications during gameplay, something fans have wanted for years.
However, the PlayStation forum reports that the update has removed the crossbar menu on many machines, making the console unusable.
According to user JadeTreeInWind, the universal fix of turning the PS3 off and then on again did not reinstate the menu bar.
The issue was widespread but not universal - it seemed the lock-up error was mainly affecting PS3 consoles over 500GB.
Sony Computer Entertainment is currently fixing the problem, stay tuned for a fix.