Instructions
Insert the UMD disc into the tray properly. Place the UMD disc, label side down, into the tray, then close it. Remove the disc from the tray and then reinsert it, and close the tray again.
Inspect the UMD disc casing for cracks or debris that has entered into the disc's enclosure. Insert another UMD disc into the PSP tray and see if the problem is the disc or the tray.
Push the "Open" button/switch near the UMD door to the left, if it is stuck in the right position. It should now open.
Inspect the UMD disc tray. Open the tray and remove any UMD disc. Look inside the tray for any dislodged, loose or broken parts that could obstruct the door. If you notice debris or loose parts, send the PSP back to Sony for repair (see Resources).