Would you be willing to answer a few brief questions about PlayStation Forums?
how can i retreve lost data
What do you mean "lost"?
If you deleted it, there is no "undelete" on the PS3 as far as I know.
If you're asking for help, I assume you don't have a backup?
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That depends on how it was lost. If you don't have backups, then you can't recover any lost data; unless it isn't really lost at all, and just isn't being displayed in the XMB.