You have a disk that you want to use with Windows. You need to format it: What file-system do you use?

A file-system specifies exactly how files are laid out on a hard disk. In other words it defines, in conjunction with the registry, where the computer would go to find files and folders stored on the disk and how the computer locates the data on the hard disk associated with the files and folders that it finds. With the Windows XP and Vista operating systems you have a choice between 2 file-systems:


(“File Allocation Table, 32 bit version”) is an upgraded version of its predecessors FAT16, and FAT12, which dates back to the 1970s.

One of the limitations of FAT32 is that a single file can be no greater than 1 byte short of 4 gigabytes.

It also has fairly lax security: Any experienced hacker should be able to easily bypass any security mechanisms and protocols with nothing more than a DOS script.


(“New Technology File System”) appeared with Windows NT in the early 1990s.

Among other things its file size limit is 2 terabytes or 2,048 gigabytes; 512 times greater than with FAT32.

Its security is pretty sturdy, and even many experienced hackers have extreme difficulty getting past security mechanisms and protocols used with this file-system.

The decision seems pretty clear-cut, judging from the above.

Should You Switch?

What if you’ve already formatted in FAT32 and added data to the disk? Have you read this article too late? Will you need to back it all up and reformat the disk in NTFS?

The answer to that is, unless you are a professional geek and extremely security-conscious and/or are using the disk in a fully-professional capacity, then no. For the average user there is a much simpler method…

A little computer magic, courtesy of Microsoft: Open a Windows Command Prompt and enter the following command. (Here I’m assuming that the drive-letter assigned to the drive in question is E: If it’s another letter then replace E: below with the appropriate drive letter.):-


The conversion utility will convert your file system to NTFS with no data loss. Once the drive is formatted as NTFS everything will work as before. Microsoft’s library article on the subject can be found here. Also see this article for a further explanation.

The outcome is, nevertheless, a little less than if you were to have backed up everything and reformatted the disk in NTFS. This will not normally be a problem for the average user, and normally will go unnoticed. If you are not an average user then click here .