I'm not sure if this has been asked, although I saw some other posts asking for save data. My problem is, I can't get copied save data to load.
My roommate played through Silent Hill 2 on my account and when we tried to simply copy his data to his own PS3 account (same system) it would not load when we started the game. We can load his native data, but the other file doesn't show up at all. Is there anything we can do to get it to show up?
We tried directly copying it using the built-in copy tool and I also tried copying it to an external harddrive and moving it that way.

I've moved data between PS3 accounts before and never had this problem. Any ideas?

Is the same name being used? Not psn id but user name
Other suggestion is to use psn plus for game saves.
As the game.save is locked to one psn user, to stop trophy cheating.

You can only use your saves on your account

It's likely a preventative measure for trophy stuff. Both PS3 and 360 have some saves that simply will not copy because they're tied directly to accounts.