I know that, but you wrote: This confuses me. The SOURCE folder is supposed to contain a copy of the original CD. That would include the WINNT.SIF that's on the CD. So what's the point in copying the file into FIX too? I can't imagine anyone having done a "Select all" in the CD's I386 folder, deselected WINNT.SIF and then copied the selection into SOURCE\I386...Either way, if the OEM supplied a copy with a modded WINNT.SIF, just put it in SOURCE\I386 with the rest. There's no need to use the FIX folder unless you actually make a change that you don't want to use all the time (it's easier to remove something from the FIX folder than it is to remove something from SOURCE\I386).