Best-effort salvage: even when an archive's index is destroyed, the files themselves are usually still inside, this finds and extracts them.
A ZIP keeps its catalogue, the central directory, at the very end of the file, which is exactly the part lost when a download truncates or a disk sector dies. But every file inside the archive also carries its own local header with its name and size, and the data follows immediately. This recovery tool ignores the missing catalogue and walks the archive from the front, header by header, extracting and testing each entry it finds. Archives that every normal unzipper refuses often surrender most of their contents this way.
The boundaries are honest: entries protected with a password are listed but skipped (there is no password guessing); entries whose compressed data itself is damaged fail their integrity check and are reported rather than silently delivered corrupt; and archives using exotic methods beyond stored/Deflate are noted as unsupported. Recovery percentage depends entirely on where the damage sits, a destroyed catalogue with intact data recovers nearly everything, while a file truncated at 40% recovers roughly the first 40%.
Why does my normal unzipper fail where this works? Standard tools read the end-of-file catalogue first and give up when it is missing or inconsistent. Walking the local headers needs no catalogue, it is slower and less tidy, but far more forgiving.
An entry says CRC mismatch, is the file unusable? The decompressed data differs from the recorded checksum: something in it is damaged. For media files the result may still play with a glitch; for programs and documents, treat it as untrusted. The tool reports it so you decide, rather than hiding it.
Can it recover a deleted ZIP from my drive? No, that is disk-level undelete work for dedicated software, done immediately after deletion. This tool salvages a damaged archive file that you still have.