While it is generally recommended to use the NTFS file system because of its stability, security and lesser defragmentation time, most of us end up using FAT32 because that is what most disks are preformatted with. Unless, we notice the “Not enough disk space error” despite disk space being available, we don't bother to change the file system.
Moreover, most of us don't change it because of the risk of losing important data and lack of time (read laziness). As Microsoft was aware of this scenario, they added a capability in the command prompt to overcome this by executing a simple command. There are many software that support this too but the Convert command is one of the easiest ways to do so. Follow the steps below to know how:-
Important: While this method works perfectly, I would still advise you to backup your data in case anything goes wrong.
FAT 32 to NTFS Conversion Steps:
1) Go to Computer, and note the name of the drive whose file system you wish to convert.
2) Click on Start.
3) Type cmd in the search bar if you use Windows 7, Windows 8 or Windows Vista. If you use Windows XP, click on Run and then execute cmd.
4) Execute "chkdsk h: /f" (without quotes) where H is the letter of the drive to undergo conversion. This checks the drive for errors and fixes them automatically.
5) Execute "Convert H: /FS:NTFS" (without quotes). H is again the letter of the drive to be converted.
6) The command prompt will start the conversion process and after a few minutes, CMD will say that conversion was successful.
7) You can check it in the properties of the drive through right click>Properties.
This works on Windows 7, Windows XP, Windows 8 and Windows Vista. I converted my flash drive's file system using these steps and it worked flawlessly. It is interesting to note that this method cannot be used to reconvert NTFS file system back to FAT32. To reconvert back to FAT32, you will need to format the entire drive which will definitely cause data loss.