Thanks for the quick answer, this way should work, but not exactly what I expect. I'm sure you'll understand the point, I can quietly upgrade my install files along time, all is ready when I need a system reinstall, without burning anything! My RunOnceEx.cmd, batchs, install files ... etc are on the D:\ drive aswell, but this part is OK, no problem. my post was not clear install files (i386,$OEM$) & unattend.txt are on D:\ D: unattend.txt |- i386 |- $oem$ I have in unattend.txt: [unattended] OemPreinstall=Yes OemFilesPath="..\$OEM$" I boot from a DOS disket, I format C:, I load smartdrv.exe I launch D:\I386\winnt /s:I386 /t:C /u:unattend.txt this works OK but the $OEM$ folder is never copied !!!! I also tried the R switch with winnt.exe, but won't work either D:\I386\winnt /s:I386 /t:C /u:unattend.txt /r:$OEM$ ==> nothing D:\I386\winnt /s:I386 /t:C /u:unattend.txt /r:.\$OEM$ ==> nothing D:\I386\winnt /s:I386 /t:C /u:unattend.txt /r:D:\$OEM$ ==>copy error Anyone can explain to me the /R switch for winnt.exe? only thing I found is: "/r:folder Specifies that a folder is created during setup. The folder remains after Setup finishes. " Well, what syntax for the path? I finally got it with absolute path and quotes: OemFilesPath="D:\$OEM$" But, since it's a DOS mode copy, folders are renamed in 8.3 !!! Conclusion so far: Looks like GunsmokingMan method will be the one, the other advantage is dynamic update, but with winnt32, how do I launch the setup the next time? in order to get the right boot I have to redo the process for each reinstall, It copies the same files each time. Any other idea welcome. Thanks MSFN, great time savings!!!