Ok, now I get it. After using TES5edit on my merged plugins it show that the individual merged plugins that are included inside the merge are also marked as master files alongside with the Skyrim.esm and the Dawnguard.esm and Dragonborn.esm when the mods require them. In some cases it is just one of the original .esp that are flagged as master, as it happens with my merge of Enhanced Blood, a single mod that comes with 3 different .esp; in this case, only the core .esp is a master (I hope that the image attached to this post can be seen, it is a screenshot of the merge info in TES5edit). When trying to merge two single mods or their.esp, the result is the same, old .esp flagged as masterfiles. And about the merges I have created so far, here they come: Pack de Armaduras (armor pack): bikini armor, Triss armor, Baraban steel helms, Baraban steel plate, baraban dawnguard, talos housecarl, armor of intrigue, Stormlord, cloaks of skyrim, cloaks dawnguard, bandolier Pack de armas (weapon pack): Billyros weapons, Merc nord shields, ceremonial greatsword, historically acurate weapons, MGsword, Loners sword, unique uniques. Lugares mejorados (enhanced locations): better morthal/ravenrock/dawnstar/docks of solitude , complete skyforge, winterhold gate, riverwood gate, underforge entrance, beakcoast cave star wars easter egg Realistic waters two: five .esp less the main one, it seems that people in the forums says that it must not be merged Estética (aestetics): eyes of beauty, brows, beards. Map Merged: quality world map (icepenguin), Atlas legendary, atlas compass Bijin + Seranaholic: bijin warmaidens, bijin wives, bijin npc, seranaholic serana, seranaholic valerica Combat evolved: core esp, enemy poison, magic and spell, stealth RealisticNights: realisticnights.esp, realisticnightsDG.esp, realisticnightsDG.esp To answer your question about a master file being inside of a merged plugin: none of my merges have a plugin that is required as a master file for a mod outside that very same merge. After watching the GamerPoets tutorial I tried not to mess around mods that need other mods as masters, and if they have, I also tried to put them into the same merge, not outside, if possible. This makes my problem, at least to me, really awkward, because this master files issue happens even with my weapons and armors merged plugins; those kind of mods, as far as I am aware of, do not need any other file to work properly that themselves. And yet, when I deactivate the individual plugins of the Ceremonial Gratsword, Billyro's weapons, Loner's sword and so on to activate the merged weapons plugin, it warns me that master files are missing, and that are that very same weapon plugin that I just deactivated.