By Michael / Last Updated March 15, 2022

Why "There is not enough space on USB flash drive" occurs?

A lot users may have met this error not enough space on USB flash drive but there is when trying to copy a large file to a USB flash drive. As you may know, USB flash drives, by default, are formatted with the FAT32 file system which has a 4GB maximum single file limit. That's to say, no matter how much free space your flash drive has, you will get this error when you transfer a single file that is larger than 4GB to the USB drive.

What to do when there is not enough space on USB flash drive but there is some?

From the above, we can learn the cause is that the USB flash drive is of FAT32 file system. To get around this problem, the easiest way is to change the file system from FAT32 to NTFS that has no file size limit. Then how to change FAT32 to NTFS file system? If there is not any important data in the USB flash drive, you can directly reformat USB to NTFS. If there is important data, you can use the following 2 methods to directly convert FAT32 to NTFS without reformatting.

Method 1. Convert FAT32 to NTFS using CMD

If you are familiar with the Windows command line, you probably know Convert.exe which can help you convert FAT partition to NTFS. It can help you convert FAT or FAT32 to NTFS file system easily.

1. Press the "Windows" key and "R" key simultaneously to bring up "Run" window.

2. Type “CMD” in the box and press Enter.

3. In the pop-up command prompt window, type: "convert x: /fs:ntfs" (“x” represent the drive letter of your flash drive). For example, if you want to convert drive D: to NTFS, you can type “convert D: /fs:ntfs”


In a few seconds, the process tells you when conversion is complete. Once it is converted to NTFS, you cannot convert it back to FAT32 or FAT using the same way. If, however, this conversion fails due to no enough free space, you can use another tool to solve this problem that flash drive says not enough space but there is.

Method 2. Convert FAT32 to NTFS with freeware

AOMEI Partition Assistant Standard is a piece of third-party software that allows you to convert FAT32 to NTFS and NTFS to FAT32 without data loss. You can follow the steps below to get it done.

Download Freeware Win 11/10/8.1/8/7/XP
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Step 1: Download and run AOMEI Partition Assistant. In the main interface, click “NTFS to FAT32 Converter”.

NTFS to FAT32 Converter

Step 2: In the pop-up window, select the option “FAT32 to NTFS”.


Step 3: Then all the FAT and FAT32 formatted partition will be listed. Just select your USB flash drive and click “Next”.

FAT32 Partitions

Step 4: Click “Proceed” to confirm and proceed.

Proceed FAT32 to NTFS

In seconds, a window will prompt out to notify you that the conversion is complete. Then the problem not enough space on the USB flash drive but there is will never happen again. As you can see, this tool can also convert NTFS to FAT32 without data loss. What‘s more, because Windows 11 only suports UEFI boot mode, if you want to try Windows 11, please convert MBR to GPT wihout data loss.