How to fix Windows 10 install.wim file too large for USB flash drive

If when you download the Windows 10 ISO image and try to copy it to a bootable USB stick, but receive the error message The file “install.wim” is too large for the destination file system, this article is intended to assist you. In this article, we will explain why you are experiencing this error, as well as what you can do to work around the error.

The reason why file too large for the destination file system error occurs is that the Windows Imaging Format (WIM) file in this download, which contains the compressed files that the Windows installer uses to install Windows 10, is just over 4.5 GB, which is way beyond the maximum file size of 4 GB for a USB key formatted using the FAT32 file system.

Drives formatted using the NTFS file system can handle this very large file, but modern UEFI-based hardware requires a FAT32 drive to boot for a clean installation of Windows.

The file “install.wim” is too large for the destination file system

To get around this Windows 10 install.wim file too large for the destination file system error on Windows 10, you can do any of the following:

1. Mount the ISO as a virtual drive and run the installer from Windows.
2. Attach the ISO file as a virtual DVD drive in a virtual machine.
3. Use various deployment tools to manage the installation on a network.

But if you need to run the installer from a bootable drive instead, in order to be able to perform a completely clean installation, you will need to use the DISM command to split the WIM file into chunks of size less than 4 GB FAT32.

Here is how in 4 steps:

1. Create a bootable recovery drive
2. Mount the downloaded ISO file and copy the contents to a folder on the local drive
3. Use the DISM command to split the WIM file into several parts
4. Copy the installation files from your local folder to the bootable USB key

Let’s see the steps in detail.

1]Create a bootable recovery drive

On a PC that is already running Windows 10, plug in a USB flash drive and create a boot drive using Windows Recovery Media Creator. You will need a drive of at least 8 GB. Make sure that Back up system files to the recovery drive is not checked. Keep in mind that all files on the player will be erased during formatting.

2]Mount the ISO file and copy its contents to a folder on the local drive

hurry Winkey + E to open File Explorer and double-click the downloaded ISO file to mount it as a virtual drive. Leave the file explorer window open and press Ctrl + N combo of keys to open a new window. In the new window, create a folder on a local hard drive and copy the contents of the mounted drive from the other window to this folder.

3]Use the DISM command to split the WIM file into several parts

Now press Winkey + R, type cmd and press the CTRL + SHIFT + ENTER key combination to open the command prompt in administrator / elevated mode.

In the window, copy and paste the command below but replace the folder name placeholder in the order with the name of the folder you created in 2nd stepand hit enter.

Dism /Split-Image /ImageFile:C:folder_namesourcesinstall.wim /SWMFile:C:folder_namesourcesinstall.swm /FileSize:3800

Once the operation is complete, check the contents of the Sources folder. You should see two new files – Install.swm and Install2.swm, alongside the original Install.wim. You can now safely delete the Install.wim file from the folder you created.

4]Copy the installation files from your local folder to the bootable USB key

Now make sure to copy everything (press CTRL + A, then press CTRL + C) folders and files and paste them into the bootable USB flash drive. You will receive a prompt telling you if you want to replace files on the destination drive, click Yes.

This time, you should not receive the error. Windows Installer recognizes the two files divided with the .SWM file name extensions and uses them to create the new installation.

Alternatively, if you’re not one to roll up your sleeves and do a dirty job, you can use Rufus or any other application that can create a bootable USB drive. These tools format the disk by creating 2 (or more) partitions. One of them formatted in NTFS, the other in FAT32. Both contain boot files, mapped to the operating system installed on the NTFS partition. In this way, it can be started from a BIOS or a UEFI system.

I hope you find this post useful!