Pasta $OEM$


A When using post-installation program installation, create the "$OEM$" folder within the "sources" folder.

After completing the installation of the programs, are the files deleted along with the "$OEM$" folder?

If not, where is it stored after installation?
NTLite copies your Post-Setup installer files under "\sources\$OEM$\$$\Setup" on the ISO folder.

When WinPE Setup runs, it will copy folders from the $OEM$ directory using these rules:
$OEM$\$$ -> C:\Windows\Setup​
$OEM$\$1 -> C:\​
$OEM$\$2 -> D:\​
$OEM$\$1\Path\Folder -> C:\Path\Folder​

Your installer files are temporarily staged under \Windows\Setup\Files or \Windows\Setup\FilesU.

NTLite creates a SetupComplete.cmd script which runs each of your Post-Setup (Machine) or "Before logon" commands one at a time, before cleaning up by deleting the Files folder. After Post-Setup (User) or "After logon" commands are run, the task deletes the FilesU folder.

If you need to permanently keep files around, then don't run them as Post-Setup tasks.

You can manually create the \sources\$OEM$ folder, outside of NTLite, and copy your files there without using Post-Setup. Because you're not using Post-Setup, then no folders are removed.