By Cherry / Last Updated March 18, 2022

User case

I am trying to copy a large file over 4GB from my computer hard drive to a USB flash drive, which has around 26GB free space unused. But I failed and received an error message that says “File is too large for destination file system”. What does it mean and how can I transfer large files to USB flash drive successfully?

File Is Too Large For Destination File System

Why cannot you copy large files to USB flash drive?

From the given error message, we can know that there is something wrong with the file system of the destination USB flash drive. So, to solve this problem, we need to first figure out what is file system? It is the way through which the operating system identifies and organizes the files on the hard disk. In Windows, the most common file systems are FAT32 and NTFS.

If you cannot transfer 4GB large files to a USB flash drive with enough unused space, there are great chances that USB flash drive is formatted with FAT32 file system. So, why cannot the FAT32 file system USB flash drive accept a singe file over 4GB? That’s because the maximun file size of a singlke file the FAT32 supports is 4GB. Therefore, even if there are enough free space on the drive, you still cannot copy large files to it. On the whole, you can transfer files to a FAT32 USB flash drive that are as large as the capacity of the drive, but the individual file should not exceed 4GB.

How to transfer large files to USB flash drive successfully?

Now that the FAT32 USB flash drive cannot save any single file that is over 4GB, you have to change the FAT32 file system to another different one such as NTFS. The NTFS now is the most widely used file system in PC currently. It can support a single file up to 16TB. So, when you need to transfer large files to USB flash drive, you can change the file system from FAT32 to NTFS. This can be done through the following two methods.

Method 1. Format FAT32 USB flash drive to NTFS (Data Loss)

If there is no important data on your USB flash drive, you can directly use the Windows Disk Management or File Explorer to format it.

Step 1. Connect USB flash drive to your computer and make sure it can be detected by your Windows. Double click “This PC/My Computer” to open Windows File Explorer, right-click the USB flash drive, select ”Format”.

Step 2. Then, choose the NTFS in the “File System” drop-down menu. Click Start.

File Explorer Format Disk

Step 3. The Windows will warn you that after formatting, the data on the USB will be erased totally. If there is no important data, you can click "OK" to continue.

So there is the question: what if the data on the USB drive is important? It will make a big damage once it lost. Fortunately, there is another way that you can directly convert FAT32 to NTFS rather than reformatting this drive. Please check out the method 2.

Method 2. Convert FAT32 USB flash drive to NTFS (Data Safe)

When there is important information on the FAT32 USB flash drive, you can first move data to another hard drive for a backup, and then format it. Or you can use cmd.exe tool to convert FAT32 file system to NTFS without damaging inside data. Do as following steps:

Step 1. Click "Start" -> "Run", type "cmd", and then click "OK". Or press Win+R to open Run dialogue, input “cmd” and hit on “Enter”.

Step 2. At the command prompt, type "convert driveletter: /FS:NTFS".

Convert To Ntfs Cmd

With this command, you can easily change FAT32 USB flash drive into NTFS file system. However, there is no command for you to convert the NTFS back to FAT32, but only reformatting it to FAT32 if necessary someday. To get rid of such limitations, you can turn to the free partition manager: AOMEI Partition Assistant Standard. It can both convert FAT32 to NTFS, and convert NTFS back to FAT32 via the “NTFS to FAT32 Converter”.

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Step 1. Download AOMEI Partition Assistant Standard, install and launch it. You will see the removable disk shown as FAT32. To convert it to NTFS safely, here you need right click the USB drive and select "Convert to NTFS" under the "Advanced" tab.

Advanced Convert To Ntfs

Step 2. It will pop out a window that you can confirm the operation. Click "OK" to continue.


Step 3. You will back to the original window, but you can see the file system of your FAT32 USB flash drive has changed into NTFS. Click "Apply" to execute it.

Apply Convert To Ntfs

To convert NTFS back to FAT32, click the “All Tools” > “NTFS to FAT32 Converter”.


Select “NTFS to FAT32” and click on “Next”.

To FAT32

Choose the target drive to convert to FAT32, and click “Next”.

Select Partition

At last, click on “Proceed”to start executing the operation.



So, when you cannot transfer larger files to USB flash drive, you can use the above methods to convert the FAT32 to NTFS. The above AOMEI Partition Assistant software is more powerful beyond safe file system conversion. You can use it to make bootable media, migrate OS to SSD, clone hard drive, clone partition, merge partitions, move partition, check partition for errors, etc. If you want more features, you can upgrade to AOMEI Partition Assistant Professional edition.