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How To Split “Install.wim” When Creating a Windows Bootable USB

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Creating a Windows bootable USB can sometimes be a challenging task, especially when dealing with large files like “install.wim”. In some cases, this file can exceed the FAT32 file system’s maximum file size limit of 4GB, making it impossible to copy directly to a bootable USB. This article will guide you through the process of splitting the “install.wim” file using a tool called DISM (Deployment Image Servicing and Management).

Quick Answer

To split the "install.wim" file when creating a Windows bootable USB, you can use the DISM tool included in Windows 10. Open Command Prompt as an administrator, navigate to the "sources" folder, and run the command "Dism /Split-Image /ImageFile:install.wim /SWMFile:install.swm /FileSize:3500". This will split the file into smaller parts that can be copied to a FAT32 formatted USB drive.

What is “install.wim”?

“Install.wim” is a Windows Imaging Format file that contains the installation files for Windows. It’s typically found in the “sources” folder of a Windows ISO file.


Before we start, you’ll need the following:

  • A Windows ISO file
  • A USB drive
  • DISM tool (included in Windows 10)

Step 1: Extract the Windows ISO file

First, we need to extract the Windows ISO file. You can use a tool like 7-Zip for this. Once installed, right-click on the ISO file and select “Extract files…”. Choose a destination folder and click “OK”.

Step 2: Locate the “install.wim” file

Navigate to the “sources” folder in the extracted files. Here, you’ll find the “install.wim” file.

Step 3: Split the “install.wim” file

Now, we’ll use the DISM tool to split the “install.wim” file. Open Command Prompt as an administrator. Navigate to the “sources” folder using the cd command. Then, run the following command:

Dism /Split-Image /ImageFile:install.wim /SWMFile:install.swm /FileSize:3500

Let’s break down this command:

  • Dism is the tool we’re using.
  • /Split-Image is the option to split an image file.
  • /ImageFile:install.wim specifies the image file we want to split.
  • /SWMFile:install.swm specifies the name of the split files. They will be named “install.swm”, “install2.swm”, etc.
  • /FileSize:3500 specifies the maximum size for each split file in MB. In this case, we’re setting it to 3500MB (or 3.5GB) to ensure it fits on the FAT32 file system.

Step 4: Copy the split files to the USB drive

Once the “install.wim” file has been split, you can copy the resulting “install.swm” files to your USB drive. Make sure the USB drive is formatted with the FAT32 file system.


Splitting the “install.wim” file allows you to create a Windows bootable USB, even when the file exceeds the FAT32 file system’s maximum file size limit. By using the DISM tool included in Windows 10, you can easily split this file and proceed with creating your bootable USB.

Remember to always handle system files with care and only make changes you understand. If you’re unsure about any step in this process, seek help from a professional or a trusted source online.

Can I split the “install.wim” file using a different tool other than DISM?

It is recommended to use the DISM tool for splitting the "install.wim" file as it is included in Windows 10 and designed specifically for this purpose. Using other tools may not guarantee the desired results.

Can I split the “install.wim” file into more than two parts?

Yes, you can split the "install.wim" file into multiple parts using the DISM tool. Simply adjust the /FileSize parameter in the command to specify the desired maximum size for each split file.

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