Fix The Not Enough Free Disk Space Error On USB Flash Drives

An error may occur when trying to transfer a file larger than 4GB to a USB flash drive. The error message states that there is not enough free disk space – even though there is plenty of free space available.

E.g. try to copy a 5GB video file to an empty 16GB flash drive – the error appears even though there is obviously sufficient free space.

The cause of this error is that most USB flash drives come pre-formatted to the FAT32 file system which has a maximum single file size limit of 4GB – you can’t copy a file larger than this, no matter how much free space is available.

The fix for this error is to convert to the NTFS file system which has no single file size limit, allowing files of any size to be stored on the drive. [NTFS is already used by your PC hard disk – that is why you don’t see this error when storing files larger than 4GB on your PC]

Convert USB Flash Drive to NTFS File System

1. Plug in your USB flash drive. For safety, take a backup of all files on it (e.g. copy them to your computer) before proceeding to the next step.

2. Enable write caching on the flash drive – this optimizes it for quicker performance and is more suited to NTFS:

  • Press Start then right click ‘(My) Computer’ and select ‘Manage’ to open the Computer Management window.
  • In the left panel, choose Device Manager (under System Tools).
  • In the right panel, double click ‘Disk drives’ to expand the list of devices – yours should be listed there:


  • Right click the USB flash drive and choose ‘Properties’ to open its Properties window then select the Policies tab.
  • Choose the ‘Optimize for performance’ option then press OK and close Computer Management:


Now you can change the file system on the drive from FAT32 to NTFS. There are two alternative ways to do this – the first (3A) tries to keep all data (no guarantees) but the second (3B) erases all data on the device. Whichever method you choose, if you didn’t take a backup earlier, do it now to avoid data loss.

3A – Convert The Drive To NTFS

  • Open an elevated Command Prompt:

XP – click ‘Start’ then click ‘Run’ and in the Run window type CMD then press ‘OK’ – this opens a Command Prompt window.
Vista/W7 – click ‘Start’ and type Command in the search box. Right click on the ‘Command Prompt’ result in the search results above it and select ‘Run As Administrator’ – this opens a Command Prompt window.

  • In the command prompt window, type convert x: /fs:ntfs then press Enter where x: is the drive letter of your flash drive. E.g. in our example below, our FAT32 flash drive is letter i: so, to convert it to NTFS, we would type convert i: /fs:ntfs
  • The process indicates when conversion is complete:


  • If there was not enough free space on the device, the conversion will fail – either remove some data from it and try again or skip to the next method which deletes all data on it.
  • Close the Command Prompt window. The drive is now using NTFS so you can transfer files larger than 4GB to it.

Tip: to double check that it now uses NTFS, open ‘(My) Computer’, right click the flash drive and select Properties – the General tab should display ‘File system:’ as NTFS:


3B – Format The Drive To NTFS. This is an alternative method which deletes all data on the device.

  • Press Start then select ‘(My) Computer’.
  • Right click your flash drive and select ‘Format…’:


  • This opens the Format window shown below. Change the ‘File system’ from FAT32 to NTFS. Ticking ‘Quick Format’ will save time but it is best to leave it unticked so that the format process can scan for any damage:


  • Press ‘Start’ to begin formatting to NTFS and press OK to accept the warning message that ‘Formatting will erase ALL data on this disk’.
  • After the process completes, a confirmation message appears.
  • Press OK then Close the Format window. The drive is now using NTFS so you can transfer files larger than 4GB to it.


16GB+ flash drives are now common but they still come pre-formatted to FAT32. As we can now copy ever larger files (e.g. videos) to them, this error is occurring more often.

However, the limitation of 4GB file size is easy to resolve by converting the file system to NTFS.

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12 Responses to: "Fix The Not Enough Free Disk Space Error On USB Flash Drives"

  1. RnZn says:

    But i got a problem….my flash drive of 8 gb space shows only 100mb total space what is the problem????

  2. Roy says:

    If you definitely mean total space (i.e. total capacity, not just free space) then the drive may be faulty or a fake size – see to test it.

  3. john says:

    This was a HUGE help. I couldn’t figure out what was going on. Now I can transfer a 5G file over! Thank you!

  4. Parvez khan says:

    u r 2 good .. thank u ; thank u very much

  5. Jim Graham says:

    Thanks!!!! No one else could tell me HOW to change to NTFS. Fantastic!

  6. Brandee says:

    Clear, complete, successful. Thank you!

  7. Paul says:

    What about when you have a 16GB flash drive (NTFS formatted) with about 9GB free and you are trying to transfer a 4GB file and Windows 10 tells you there is not sufficient space? I have this problem all the time since upgrading to Windows 10 and sometimes it’s with smaller files and the entire flash drive is free. This happens on multiple flash drives.

    Has anyone else had this problem and found a workaround? I haven’t seen any responses from Microsoft about this issue.

  8. kat says:

    Thank you , this was exactly what was wrong, I’m just moving the files over in sections instead of a group, perfect!!.

  9. Shahid Rabbani says:

    Solved… Great

  10. JY says:

    Thanks so much! This was so easy to follow and it solved my problem! Interesting information.

  11. Monica Saunders says:

    It worked!! Thank you!

  12. Hamid says:

    thanks for the answer, it is helpfull but NTFS will not be work on my TV …I want the glash memory on my TV. Thanks