Why does Explorer say "File too large" for my custom file system, when the problem has nothing to do with the file being too large (heck it's not even a file)

When Explorer copies files around, it doesn't really know what the maximum file size supported by any file system happens to be. (That information is not reported by .) So it guesses. If the file system name is or , then Explorer assumes that the maximum file size is 4GB − 1. Also, if a file operation fails with the error , and Explorer ca...