Unknown extension 'udatasmith'

When I try to import a udatasmith file in 4.21 I am getting an “Unknown extension ‘udatasmith’” error.

Is anyone else getting this error?

You are probably performing the import through the normal UE4 import process, but Datasmith has a different process.

You need to use the “Import Datasmith” button that appears on the toolbar when the Datasmith plugin is installed.

Thanks Stephen, that was it!