Seagate external drive not recognized

Hello. I have 3 external hard drives all formatted with MacOS Extended (journaled). The MacBook Pros do not recognize the 1 TB and 2 TB Seagate drives. They do recognize the 120GB Western Digital drive.

The Mac mini recognizes all 3 drives.

MacBook Pro mid 2012, MacBook Pro mid 2015, Mac Mini (All are OS 10.13.3).

I've tried different cables. I've reformated the larger drives. Connections are only direct (no hub).

Neither of the Seagates are recognized in the MacBook Pro drive utility.

It seems that the Seagate recognition problem started when we upgraded to 10.13.3.

I've tried both USB ports. I've been through Seagate support.

Anyone know what the problem might be and a fix?

Regards,

craig