Hi,
Your screenshot shows install.swm, which is a split Windows image and cannot be modified directly. Instead of adding the folder through 7-Zip, use the $OEM$ folder method.
In your extracted Windows installation files, create this folder structure outside install.swm:
sources$OEM$$$\Setup\YourFolder
Replace “YourFolder” with your folder’s name and put your files inside. Include this folder structure when rebuilding your bootable ISO or preparing your installation USB.
During a standard Windows Setup installation, these files will be copied to the Windows folder, normally:
C:\Windows\Setup\YourFolder
This avoids modifying install.swm.
Microsoft documentation: