Nope, I don't, except if I forget to correctly link the armature and mesh. I only use Source 1 FilmMaker.

Does it work in Source 1 FilmMaker?

Well, at least that doesn't seem to be the case anymore (or else I have a really bad memory).

Is that a typo of Source 2, or is that referring to ages long past or something?

I think any flexes embedded into the DMX will be loaded into Source 2.
I'm not sure about VTAs and such, though, or if DMXes will even work.

Export somewhere else, run Blender as administrator, or give everything full permission for both read and write in the folder you're trying to export to.

No. But don't worry, Blender Source Tools already imports UV maps.

le jouet の投稿を引用：

P.S. Cant find new decompiler of VMDL files.

It doesn't exist yet, simple as that. But Crowbar might eventually be what you're looking for.

Yeah, I was going to mention that too, but I first remembered it after I went to bed.

Pte Jack の投稿を引用：

Ok, seen... When I exported the model as a DMX Auto Smooth WAS off, however when I imported the DMX back into blender, the model came back in and Auto Smooth turned on.

There's nothing in a DMX saying whether something has custom normals, only what the custom normals are, and there's no reliable way to check if any custom normal differs from the default normals when imported (that doesn't involve huge extra importing time from individually checking every single vertice's custom and default normal of every single face), so it's always "this has custom normals" when imported.
Oh, and should I mention that different applications (Blender against 3DS Max, for example) may still very likely save different normals to the mesh, making it so that that "is this a custom normal" method would still only work for models already exported from Blender?

Pte Jack の投稿を引用：

(Is there a switch in Blender that I forgot to set???)

No there's not, it's just broken. (Especially/Mostly for hard-ware morph-style flexes.)

Edit: ...Actually, in the export for Source it's just (slightly-ish) broken, in Blender it's just a limitation of Blender. As of version -something-, importing DMXes with the Blender Source Tools also imported custom normals... but I don't think flexes/shape keys can have their own set of custom normals, so they just use the "custom normals" of the reference pose mesh thing... and while those normals are affected by the faces of a model squishing, stretching, and rotation, they're not smoothed with each other, unlike in Source. (Just try moving some bones of the armature a little around in pose mode, you'll see what I mean.)