Why Your SD Card Won't Let You Transfer Files Bigger Than 4GB, And How To Fix It

SD cards formatted with the FAT32 file system cannot accept any single file larger than 4GB, even when the card has ample free space, because the decades-old format records file sizes using a 32-bit number capped at 4,294,967,295 bytes. The limitation traces back to Windows 95-era technology that remains widespread because of its near-universal compatibility across devices. The card itself is almost certainly not defective; the constraint lies entirely in the file system, and reformatting to a modern format resolves it. The issue is mostly harmless for documents and photos but becomes a practical problem for users moving large video files or disk images. Users should watch for which file system their card ships with and whether their devices support exFAT or other formats before reformatting.