Enabling CAD formats in the plugin section has no effect - can't import CAD files

Hi peeps, I’m so sorry if this is an obvious query, but I can’t seem to resolve it. I’m trying to import CAD data (step and i​ges) into UR4 but the Datasmith import window shows all the format’s greyed out. I have the plugin enabled and I’ve restarted the engine countless times. Is it by chance because I’m on a Mac or something? Thanks in advance - Rob