everytime i run it on my psp and then exit it makes my psp memory card say no games available when i access it, but there are isos and csos in the iso folder

im on custom firmware 5.00 m-33 and the memory card has worked for 8 months

i can reformat to solve the problem but that means i have to move games and that takes awhile

is it a bad file or does it happen to everyone? or is it something else?