The PSP has limited memory compared to modern computers, and some highly modified save files may not work on real PSP hardware. As one forum user noted, "I think they won't work on a PSP (it will run out of memory). Thank god there's emulation". For the best experience with mod save data, using PPSSPP on a PC or Android device is recommended.
This is the most frequent error. It occurs when: The PSP has limited memory compared to modern
The [UPD] mod save data for Naruto Shippuden: Ultimate Ninja Impact likely includes: The PSP has limited memory compared to modern