This is just a quick note, as I spent WAY too long trying to figure out why pretty much any of the Oblivion mods I was trying to install that were supposed to override textures weren’t working. I had the ArchiveInvalidationInvalidated mod installed, and nothing I tried worked.
As it turns out, the Steam install of Oblivion does weird things with the dates of the BSA files that are part of the retail package and DLCs. This causes the mod files to appear older than the BSA files, so they don’t load.
So, time for a quick PowerShell fix. Open PowerShell and go to your Oblivion data folder:
cd \Program Files (x86)\Steam\SteamApps\Common\Oblivion\Data
and run the following command:
dir *.bsa | % { $_.CreationTime = '1/1/2006 10:05'; $_.LastWriteTime = '1/1/2006 10:05' }
This will set the creation and last update time for all of your BSA to 2006, which should be well old enough for the mod files to take precedence.