Hey,
Like many of you I got the horrible patch that made the game go crazy.
Game crashed as soon as I hit play.

Turned out Archive Invalidation was to blame.

Here is the fix:

Open all 3 ini's (Fallout, FalloutPrefs and Fallout_default)

Search for "SArchiveList"

Replace that line with this:

SArchiveList=Fallout - Voices1.bsa, Fallout - Sound.bsa, Fallout - Misc.bsa, ArchiveInvalidationInvalidated!.bsa, Fallout - Textures.bsa, Fallout - Textures2.bsa, Fallout - Meshes.bsa


Unless your using the New Vegas Archive Invalidation then it should be this:

SArchiveList=Fallout - Voices1.bsa, Fallout - Sound.bsa, Fallout - Misc.bsa, AII-FNV!.bsa, Fallout - Textures.bsa, Fallout - Textures2.bsa, Fallout - Meshes.bsa


Have fun

Thanks for this excellent solution

Actually you shouldn't need to edit the ini at all if you rename it Fallout - AII.bsa