Thank you for the very elaborate reply, appreciate it :thumbsup: But I am sorry to say that this was not what I meant :confused: Basically what I am trying to do is this: I want to create a single .ESP (my "main" .ESP) containing every new weapon I add to my game, so I have them all in one "place", making it easier to use the data to build replacer mods for my personal game. But this requires that the IDs doesn't change in the main .ESP, when I add another .ESP to it. So far I have only found tools that will merge .ESPs indiscriminately, resulting in the renaming of IDs in both .ESPs, which will then break any replacers I have made using the main .ESP as a master. What I am looking for is a tool that will merge new .ESPs into the main .ESP without it touching the existing IDs of the main .ESP. Hope that makes it clearer :sweat: