Hi Sailors,
Thank you for reporting this. This is a known issue that affects some FBX imports (UE - 3032). I’ve updated some notes and added this AH post to that bug report as well.
As a workaround you can import the mesh into UE4 by unchecking the “Generate Lightmap UVs” when the Import Options window is open. This is where the hitch is happening that is causing the crash. If you need/want lightmap UVs you’ll need to create them in your modeling software for this particular mesh or any meshes that are causing the crash to occur.
Once a fix has been submitted I’ll verify and update this post with any and all relevant information.
Thank you!
Tim