The Import Multiple Solid Parts as Assembly option is no longer available. Files that contain multiple-solid parts are imported as Inventor multi-body parts. Use the Make Components command to create part files from the individual bodies.
This change affects import options for JT, Parasolid, IGES, STEP, NX, and SolidWorks files.
For SAT files, the option Import as a Single Part controls the translation of multiple-solid parts. If enabled, solids are imported as bodies in a single part. If disabled, each solid is imported as a part in an assembly.