Well I finally found it. First, no folders showed up under c/users/myname... but when I tried to create a new AppData folder there it offered to merge. So it exists but is not visible or accessible by normal means. I searched AppData in file explorer and it appeared, but opening it revealed "this folder is empty". I then searched "local", which is in AppData despite the folder saying it is empty. So I opened local/fallout4 and finally found plugins.txt, which the explorer could not find itself. (also, it is not listed as being located in c drive. It just says myname/appdata/local. not sure if that is just shorthand or actually matters) In my plugins.txt, all the mods had * before them. I unchecked read only, deleted all the * , checked read only back on, and that solved the error messages. I don't know how or why any of this happened. Probably NMM related. I still have to test for that CTD on save and hope it's gone. Trying to get around all these issues just to play the game could earn me like 6 credits in college. EDIT [actually that only fixed the errors with fo4edit and loot not recognizing them properly. But it disables the plugins. When i reactivate them, plugins.txt automatically has the * back, and the error messages return. Also, after some experimenting I discovered that the crash doesn't happen 100% of the time and isn't triggered by building in one specific spot. It happens if I use a mod-added wall piece to fill the gaps in any sanctuary house walls. If I use vanilla wall pieces it doesn't occur. If I place mod wall pieces anywhere except inside the house walls, it doesnt occur. But placing a couple mod walls inside the sanctuary house walls gives me like a 70% chance of CTD upon saving. Plus I still get that blank "this save relies on" message. I don't know what to do anymore, it's slowly driving me nuts.] EDIT 2 I determined that the wall piece causing the CTD was from Homemaker. I went to the mods nexus page and saw an updated version, downloaded it, and that got rid of the "this save..." warning message. It still causes the crash though. I guess Ill just use vanilla walls in those spots instead. My fo4edit and loot issue is still unresolved but maybe i have to update them too. Ill take another stab later.