After booting up our copy of Call of Duty: Modern Warfare 2 for the first time, you will be prompted to download a 15mb patch for the game. However, it seems that this patch is causing issues with the trophy system. On playing the game for the first time, the trophy list should be loaded on to your console, but this isn’t always the case. As a result, you will not be able to earn any trophies unless the list has been loaded.
Install the patch and see if the trophies load up on your first attempt. After starting a new game, press the PS button and check your trophy collection. If it isn’t there, delete the patch and boot the game without installing the patch, starting a new game to install the trophy list.