If you have files that are bigger than 4GB in size, you will find that you can’t back them up to your external hard disk, even though it has 1TB of storage space. The reason being, when you first bought the hard disk, it is pre-formatted with FAT32 format, and in case you don’t know, FAT32 has a 4GB file size restriction. This means that it can’t store files that are bigger than 4GB in size.
A good way to overcome this is to reformat the external hard disk to NTFS format. NTFS does not has a 4GB file restriction and can be accessed easily from Windows, Mac and Linux (with the help of NTFS-3G).