Here's a quote from another post, by Merilian. Link to post
worked for me after I reinstalled the body mods. I had the exact same problem, though other mods e.g. adding new items worked just fine...
EDIT: In my Skyrim.ini located in C:\Users\YOURNAMEHERE\Documents\My Games\Skyrim, under the archive tab there was: bInvalidateOlderFiles =0. I had previously not attempted to tamper with this for I thought resetting my Archive Invalidation would be enough.. After changing it to the value to 1, everything functioned again.
PS: Thanks Oubliette.
Hope this works for you too, though it's a little late now.
EDIT: I also started a new game for this, haven't tried if this applies to older savegames, but it should
EDIT: It does ;)
