Eu encontrei a solução aqui .
Execute o script abaixo em Deployment Tools Environment
:: Rename the original install.wim file.
rename D:\sources\install.wim install.bak
:: Create an empty temporary directory.
mkdir D:\sources\dummy
:: Create a new install.wim file with dummy image.
dism.exe /Capture-Image /ImageFile:D:\sources\install.wim /CaptureDir:D:\sources\dummy /Name:dummy /Compress:Max
:: Export the first Windows image to the empty install.wim file.
dism.exe /Export-Image /SourceImageFile:D:\sources\install.bak /SourceIndex:1 /DestinationImageFile:D:\sources\install.wim /Compress:Max
:: Delete the first dummy index in install.wim
dism.exe /Delete-Image /ImageFile:D:\sources\install.wim /Index:1
:: Delete temporary directory.
rmdir D:\sources\dummy
Agora você pode abrir o install.wim no WSIM.
Além disso, você pode excluir o arquivo original (install.bak) e criar a mídia inicializável usando oscdimg.exe