Just purchased a new 12 x 2 G raid drive. Connected to 2014 iMac w High Sierra. Doesn’t show up. Rebooted, restarted, reconnected etc. Still doesn’t show up anywhere.
Which version of the G-RAID did you purchase? Is it the Thunderbolt 3 version? How are you attaching it to an older iMac exactly. Are you using a TB2 to 3 adapter? USB type C to A adapter?
Have you checked the Disk Utility to see if it shows up there?