Importing animated FXB always fails?

Thanks again,

Ok, perhaps I have misunderstood something. What I want to achieve is following:

  1. Use the skeletal mesh I sent as a character.
  2. Use the animation fxb as animation source.
  3. Yes they have different skeletons as they come from different source! They both have human bone structure, although in different order. I want to use UE retargeting to change all animations compatible with the character skeletal mesh. Basically this is the workflow with unity3d. Import character fxb → import animation fxb → tell Unity with rig editor what bones in the animation file are used as hip, spine, neck, etc…
    Perhaps I have misunderstood this whole process with UE?

So does this mean I can’t import animations that have not been strictly made for the skeletal mesh in the scene?
Then what is UE’s retargeting used for?