How to fix your corrupt USB flash without having to format Software Clinic 01

Clara cant access files on her USB flash drive. Windows asks to format it. But theres still important data on it. To get it back, she has to repair the drive.\r
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Many problem on usb flash drive; 1. file system RAW, or file system unknown 2. used space 0, free space 0 3. wrong detect capacity, example 4gb detect 10,6Mb .