the install.wim of Windows 10 iso Images which contains multiple OS Versions is usually greater then magic 4GB broder.
Therefore it is not possible to copy this file to an FAT32 formated USB Stick because FAT32 has a file size limit of 4GB.
A way to shrink the wim file is to extract only the OS Version you want to install. dism can do this since Windows 8. Copy the install.wim file to your harddisk, i.e. D:\temp and see which Windows Versions are included
D:\Temp> dir D:\Temp\install.wim 03.08.2017 22:57 4.810.578.598 install.wim D:\Temp> dism /Get-WIMinfo /wimfile:install.wim Deployment Image Servicing and Management tool Version: 6.3.9600.17031 Details for image : install.wim Index : 1 Name : Windows 10 Pro Description : Windows 10 Pro Size : 15.870.553.953 bytes Index : 2 Name : Windows 10 Home Description : Windows 10 Home Size : 15.688.600.726 bytes
Then export the OS Version to a new wim file and set maximum compression. Let use assume Windows 10 Professional which is Index 1:
D:\Temp> dism /Export-image /SourceImageFile:install.wim /SourceIndex:1 /DestinationImageFile:install-new.wim /DestinationName:"Windows 10 Pro" /compress:max Exporting image [==========================100.0%==========================] D:\Temp> dir install-new.wim 03.08.2017 23:08 4.095.320.725 install-new.wim
Now the size does not break the 4GB size limit and can transferred to an USB Stick