Some SD cards will reject any single file larger than 4GB, even when the card is nearly empty. The culprit is the card's file system, not its capacity.
The limit applies per file, not to the total. A card can hold dozens of 3GB files and still refuse one 5GB file. The file system behind that wall is FAT32, which caps a single file at just under 4GB. Total capacity and free space do not change that, and the fix is a short one.
Check the format first. On Windows, open This PC, right-click the card, choose Properties, and read the File System line. On a Mac, select the card in Disk Utility and look at the format listed. If it says FAT32, that explains the error.
Then reformat to exFAT. exFAT is a newer file system with no practical 4GB ceiling for everyday files. Reformatting erases the card, so copy everything off it first. On Windows, right-click the card, choose Format, and pick exFAT. On a Mac, use Erase in Disk Utility and choose ExFAT.
Which cards are likely to be affected? Under the SD standard, SDHC cards (up to 32GB) use FAT32, while SDXC cards (64GB and up) use exFAT. So a 32GB card is a more likely suspect than a 256GB one. A card that was reformatted by a camera, a console, or a formatting tool can end up FAT32 whatever its size, which is why checking beats guessing.
The catch is compatibility. Some older cameras, car stereos, and other devices read only FAT32, and a card formatted exFAT may show up empty or unreadable in them. Check the device's manual before wiping a card you rely on there.
The 4GB wall matters more each year because modern files keep growing. A few minutes of high-bitrate 4K video, a disk image, or a large game file can cross it, so the old limit now shows up in ordinary use.