I had to take some additional steps, that is, make an ArchiveInvalidation.txt file with a list of all the textures in it that are loose. Someone on another forum posted a tutorial:
That's the same thing as NOT using the ArchiveInvalidationInvalidated! method. That's just using the old method, so that's not a good solution nor is it and answer to the question. The question being whether the ArchiveInvalidationInvalidated! method still works.
Steam probably saw changes to the file and recreated it. You know, failed validation kind of thing?
So, was the file overwritten? FalloutPrefs.ini or Fallout.ini in the savegame folder? Look at the date/time on the files.
I make it a habit to always make a copy of the ini files when I change them so that if they get changed by someone else I'll know about it.
I'm still confused about which file(s) to modify. I assume you should never modify the Fallout_default.ini file (in the FalloutNV/Data folder) unless you wanted some particular options to always be set to a certain value when you've started a new game or deleted your old files (in the savegame folder) - and I've made a copy of that file too. I'll note that Fallout.ini and Fallout_default.ini appear to be identical and the the Fallout.ini file is marked read-only. I assume that means that the user should not modify that file. As far as I can tell the game has not changed my Fallout.ini file since I first ran the game. I've only just gone out Doc's door so far - collecting and installing MODs is all I've done for the last two days.
I have put all my edits into the FalloutPrefs.ini file, it is marked read-write and I believe that the game may write settings to the file such as changes made in the Options menu. I believe that the FalloutPrefs.ini file is the proper file to modify for ordinary added and modified stuff.
So now I'm adding the manual ArchiveInvalidationInvalidated! method to the FalloutPrefs.ini file along with my other edited settings. I hope that works.
I should also note that I've made my .../remote/ folder unwriteable with the permissions trick and emptied the folder - so that Steam won't mess with my savegame files or try to overwrite the FalloutPrefs.ini file.