Why are all of my external drives showing up as UNSUPPORTED? Why can't SMART Utility scan these?

This is a limitation of the external drive enclosures, and possibly the drivers used. Put simply, there are special commands in the ATA specification (the protocol that the drives use to communicate with the motherboard, which includes IDE and SATA) that the drives understand to access the SMART data. Most external drive enclosures only support the bare minimum of the ATA specification over the external connection interface (USB, FireWire, or eSATA), and that does not include the commands to access the SMART data. There are a few enclosures that do support it, but they are few and far between. Hopefully this situation improve in the future.
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