Data Read/Write Errors
The leading cause of corrupted PlayStation 2 save data is interruption of the read/write operation of the card. Whenever you save or load data, your PlayStation 2 interfaces with your memory card. If this operation is not given time to complete correctly, data can be corrupted. Not only must the PlayStation 2 not be turned off or reset during memory card reading/writing, but the memory card and game disc must not be removed either. This is why many PlayStation 2 games display a warning not to touch the console or memory card while saving or loading.
Defective Cards
While the PlayStation hardware itself is manufactured only by Sony, many third-party manufacturers, both authorized and not, have produced peripherals for the machine. As well as controllers and system cables, this includes memory cards. Third-party memory cards can sometimes contain inferior chip sets, which can lead to errors saving or reading data from games. To prevent data corruption due to inferior system hardware, use only first-party Sony memory cards or cards whose packaging carries the MagicGate logo, indicating a Sony-certified product. The price may be a little higher but this cost ensures the highest level of data protection.
PlayStation 2 Errors
PlayStation 2 save data may become corrupted if the machine is under system stress during save or load operations. Conditions which can place a PlayStation 2 system under stress are excessive heat, moisture, dust or poor ventilation. These can cause the console to develop trouble reading and displaying games and video as well as interfacing with the memory card. You can prevent these errors by ensuring your PlayStation 2 is operating in a cool, dry, well-ventilated area.
Cross-Corruption
Corrupted PlayStation 2 save data can spread on a memory card. Because read/write operations can involve moving data from one area of the memory card to another, it is possible for corruption to spread between save files. If you have a corrupted file on your memory card that cannot be read by your PlayStation 2, delete the file from the system's dashboard to prevent corrupting other data.
Damaged Cards
PlayStation 2 save data can be corrupted when the memory card becomes physically damaged. If your memory card is cracked, subjected to excessive force, heat or cold, or if the connector plates or internal workings of the card come into contact with liquid or dirt, the card's data can become corrupted. Guard against this by keeping your memory card in the slot of your PlayStation 2 or the protective cover with which it is packaged.