Windows ISO Too Large for USB
In Windows 11/10, you may choose to download an ISO file to install the OS. However, when copying ISO files to a USB drive, you receive an error message saying the file ‘install.wim’ is too large for the destination file system. Or when you need to copy & paste the install.wim file to a USB drive from Windows 11 ISO to the Windows 10 installation USB to install Windows 11 on an unsupported PC, install.wim too large appears.
This issue appears primarily because the install.wim file is beyond the maximum 4GB file size for a USB flash drive that uses the FAT32 file system.
To solve this error, some of you may consider using NTFS as the file system of your USB drive since it supports a file that exceeds 4GB. But the most modern UEFI-based PCs require a bootable USB with FAT32 file format to boot Windows installation.
Related post: NTFS VS FAT32 VS exFAT: Differences & How to Format
So, how can you get rid of the trouble? In the following part, you can find the top 2 solutions and now let’s delve into them.
Install.wim File Too Large Windows 11/10
Extract Needed Index from the Original Install.wim to Get a Smaller One
According to some users, this way can help you a lot. See the steps below:
Step 1: Mount the ISO image and extract the required install.wim from the sources folder. Sometimes you see install.esd instead of install.wim.
Step 2: Run Command Prompt with admin rights – type cmd into the search box and click Run as administrator.
Step 3: Type dism /Get-WimInfo /WimFile:”I:\sources\install.wim” and press Enter to get the index that represents the needed Windows edition. Replace I:\sources\install.wim with your correct path to the install.wim.
Step 4: Type Md C:\Mount and press Enter to create a Mount folder at the root of the C: partition.
Step 5: Execute this command Dism /Export-Image /SourceImageFile:”I:\sources\install.wim” /SourceIndex:6 /DestinationImageFile:”c:\Mount\install.wim”. Here 6 refers to Windows 10 Pro, and you can replace it based on your need.
This operation can reduce the install.wim file size to less than 4GB. But sometimes this method cannot fix install.wim too large. In this case, move to the next way.
Split WIM File into Small Ones
When receiving the file install.wim is too large in Windows 11/10, you can choose to split this file to many small pieces to fix it. See these steps:
Step 1: Open Command Prompt with admin rights.
Step 2: Type Dism /Split-Image /ImageFile:I:\sources\install.wim /SWMFile:I:\sources\install.swm /FileSize:4700 and press Enter. 4700 means the maximum size in MB for each of the created split .swm files.
After that, you can see multiple .swm files in the sources folder – the first .swm file is called install.swm and the remaining files are install2.swm, install3.swm, install4.swm, etc.
Then, you can copy all the ISO files to a USB drive and install.wim too large won’t appear.
Use Rufus to Create a Bootable USB Drive
To successfully get a bootable USB drive, we recommend using Rufus. This way can avoid the error install.wim file too large. Just download and launch it, connect a USB drive to your PC, choose the ISO image, configure something and you can start the ISO burning process.
After preparing a bootable USB drive, you can start to use this drive to perform a clean installation of Windows 11/10. Note that this process can erase your personal data, so you should create a backup for important files, especially files saved on the Desktop. Here, you can run MiniTool ShadowMaker and start file backup.