You are not actually creating physical storage. You are making the logical storage more efficient. On a standard 16GB SD card, users typically recover an extra 1.5GB to 3GB, not a full 16GB. However, on highly fragmented drives, the "free space" can appear to double.
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: Once you try to save files beyond the actual physical limit of the drive, the data will overlap or fail to save, leading to permanent file corruption and loss. sdata tool v100 double usb or sd card space free