External Drive Disconnects at Display Sleep

External G-drive worked find until upgrade to Monterey.

Now: MacOS issues warning: "Disconnect hard drive before powering off" despite not powering off or disconnecting the cable. External drive disappears from Finder.

Occurrence is somewhat random, but usually after display shuts off. I have inspected Energy Saver settings.

How can I assure continuous connection with this G-drive hard drive?