phaolo and jaclaz, you both are mentioning iterative approach. nLite does support multiple sessions, it is not made to be used only once, just that it is recommended approach because of what I will explain next. There is confusion with presets, as you start piling up last sessions, they would need to be merged. If something was removed then adding hotfix for it popups up missing files messages and people wonder why it is not integrating. Update packs can literally change everything, and nLite can't track that, or should I say it would be a nightmare to map all changes into entities and undo packages. nLite gives you the ability to save whatever it does in a single file (plus unattended preset for safety reasons), so you can easily start fresh by copying your prefer source. That source can be whatever you want and made from whatever steps you want. Configure that source before nLite, back it up, and there is your nLite undo. I see no real problem there, maybe you can give me a scenario where you must use nLite many times and prefer to use multiple presets each time. Of course it would be ideal if nLite detected that you already enabled a certain tweak which can be done with a group policy, reg entry, a batch script, an addon, but that is just dreaming as the combinations are too great. And lastly, returning missing components is simply too much work for a non-issue, simply start fresh and use same preset with that component not removed, simple as that and requires no tricky - easy to messup - multiple combinations of post-hotfixing returning of old component and who knows what other combination. In short, if you find a bug that is caused by running nLite multiple times, please report. To undo what nLite did, use your source on which you used nLite and configure the preset differently. And in case you get mad at me not understanding, I am not dissagreeing with you that it would be ideal, I am just saying it is not practical to have undo from nLite itself, it would be much more complicated and prone to bugs.