Things You'll Need
Instructions
How to Fix a PSP Memory Stick
Upgrade your PSP's Firmware (its operating system) before doing anything else. Firmware 5.0 solves many software problems that are encountered with older memory sticks. You can upgrade it by simply connecting your PSP to any wireless connection through its WiFi. Once a connection is established, the PSP will update itself automatically.
Check to see that your memory stick's plastic tongs, the small sticks that separate each connection, are straight. If one is bent, your PSP will not recognize the stick.
Remove your memory stick if it still does not work. Insert it into a PC with a memory stick slot. You will most likely be able to see all of your saved files. If so, continue to the next step. If you still cannot see your files, then your memory stick is defective, and it is not the PSP's fault.
Copy your files from the memory stick to the hard drive.
Format your memory stick using the "Format Disk" option in Windows. Open Windows Explorer, and find your memory stick listed in the "Drives" section. Right-click on the memory stick, and click "Format." Follow the on-screen instructions in the windows that pop up.
Insert your memory stick into your PSP. It should recognize the disk now. However, you now need to format the memory disk again with the PSP.
Go the PSP main menu, and select "Settings." Then select "Format Memory Disk."
Put your memory stick back in your PC, and return the files you removed earlier. When you reinsert the stick into your PSP, it should now see all the files.