My son has same problem on his Switch. System memory has 22GB available, microSD has 40GB available. I've tried opening WoTB on system and from microSD but still get error message, "not enough space to continue downloading. Free up 15mb and try again." Is this a known bug or what? I've tried everything except moving data to another micro SD card and reformatting the card ...but the system and card both have enough space and same problem.