Q: I have a new 250 GB external hard drive (WD). I try to move a file that is 4.88GB across and it says 'the file is too large for the destination file system. Thanks very much. also - what is an allocation unit size?
A: You need to use NTFS. Fat 32 has a size limit of 4GB - 1 byte. Allocation Unit Size is the minimum amount of space a piece of data will occupy on the disk. NTFS uses blocks of 4096 bytes (4K) so even an empty file will take up 4K of space. All files on the disk will have a file size divisible by 4k. Files might appear larger than they actually are and the amount of usable space on a disk is actually a bit smaller than reported. Good luck.