When transfering a dvd iso file (larger than 7gb) to USB drive (or any external storage), there is this error message: too large for destination file system. It is usually because the external drive is using FAT32 system, which has a limit of 4GB maximum file size. It has to be formatted as NTFS. The second choice would be to split and rejoin the files, I would rather one formats it.
This is thanks to http://helpdeskgeek.com/help-desk/file-is-too-large-for-destination-file-system/