Okay, I'm sorry to have to make a thread about this, usually I'm quite fine with finding the answers to issues with google. But with this I'm totally stumped.
Sometimes when I undo things when working with edit poly, something strange happens. A bunch of verts delete themselves, normals get broken, verts moved...
There is never a way to undo this. I have to reload my last save. Today I loaded the object I was working on to find it like this:
which was certainly not how I left it. If I delete the most recently edit poly, the state is fine again.
I have absolutely no idea what is causing this. I've been using 3ds max for maybe 9 months now, and this is only recently started happening.
I'm using 64-bit 3ds max 2012.
I would be really appreciative of help, it's getting really annoying having my work destroyed :/