Things You'll Need
Instructions
Check the SD card to find out whether the write protection switch is pushed down. Look on the side of the card for this small switch; when pushed down, it prevents you from reading or writing data to the SD card. Push the switch back up, and the PSP can begin using the card again.
Spray compressed air into the PSP's card slot to remove dust and other debris stuck inside the card slot, preventing it from reading the card.
Format the card. If your card has become corrupt, the only way to correct the problem will involve formatting it. Insert the card into the memory card slot on your computer, then click "Start" and "Computer." Right-click the removable device icon, and click "Format" to remove any saved content from the card and return it to its factory settings.
Power down the Sony PSP, and remove its batteries. Wait a few minutes, then power the hardware back on. The Sony PSP should now detect inserted SD cards, as powering it down will have reset many of the internal features on the mobile device.