IsoPuzzle is program which help you to recover as much as possible data of damaged, bad burned or scratched CDs or DVDs. Iso Puzzle creates an iso image of the disc that you place in the drive. All good sectors, that are those that can be read without errors, are written correctly and flagged as good while bad sectors will be flagged as bad.
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That means that some portions of the the CD can’t still be recovered. I think this software is great for slightly severed CDs.