I have a weird problem with a nightgown. I made some changes to the fat morph of the mesh and updated the mesh and checked it out in Bodyshop, all good. I decided to change something else and reopened it in Milkshape and it had reverted back to before I made any changes. Did it all again and it did the same thing. Even extracted the one from the SimPE file and that had reverted as well.

Anyone know what might be causing this?

Cache files, maybe? But only if the old copy is causing problems ingame but the files appear fine out of game.

Most likely you're working on an old copy of the file for some reason or another. That's the most likely culprit, as meshes don't usually revert to an old copy all on their own.

Personally I tend to rename files with version numbers until I'm done with them, because that tends to take care of the "am I working on a new or old copy of this file?" question, and also makes it a bit easier to identify old copies if they've decided to hang out in a random Downloads subfolder or SavedSims, which happens from time to time (I suggest a TEST folder, with nice big capital letters for projects you're currently tinkering with and testing out, and not letting anything hang out in for instance SavedSims - could be there's a copy of the old file there).

Tried giving it a totally new name after I worked on it and it still reverted when I reopened it in Milkshape. Bizarre.

That's really strange. Maybe you forgot to save or some such.

Still no idea what went wrong, but saving it in a new place worked. Hope my folder isn't bugged; I have a lot of meshes in there.

Thanks for the help!