OWC Gemini Thunderbolt RAID not mounting drives after restart — requires full power drain

I’m looking to see if anyone else has experienced this behavior with the OWC Gemini Thunderbolt enclosure on Apple Silicon Macs.

The enclosure itself always shows up (Thunderbolt device, HDMI output works, LEDs light), but after a restart or cold boot, the internal drives do not mount at all — they’re missing from Finder and Disk Utility. The only way to get the drives to appear is to fully unplug the enclosure’s power and wait for a complete power drain, then reconnect power and Thunderbolt.

This happens regardless of:

RAID mode (RAID 0 or Independent)

Drive type (SSD or HDD)

macOS version

Cable or Thunderbolt port

Simply rebooting the Mac is enough to make the drives disappear again.

Has anyone else seen this with the Gemini or similar Thunderbolt RAID enclosures? Is this a known firmware/initialization issue, or is there some macOS or Thunderbolt behavior I might be missing?

Mac mini (M4 Pro, 2024)

Posted on Dec 21, 2025 7:07 PM

Top-ranking reply

Vernon Alexander Author

Level 2

466 points

Posted on Jan 9, 2026 8:51 AM

Thanks for sharing that — unfortunately, that mirrors my experience almost exactly.

For what it’s worth, I ended up returning my Gemini and replacing it with a Mediasonic 4-bay enclosure. It mounted immediately, survives reboots without needing power removal, and has been flawless so far — at roughly half the price.

What still puzzles me is how OWC continues to sell the Gemini given the mounting and power-state issues multiple users are seeing. Functionally, it behaves like a USB 3 enclosure bridged to Thunderbolt, with none of the reliability or advantages you’d expect from a true Thunderbolt storage device.

After switching enclosures, the problems disappeared entirely, which strongly suggests the Gemini itself is the weak link.

I’m still going back and forth with OWC support trying to get a straight answer on whether this behavior is expected for the Gemini. They consistently avoid answering that question directly. Rather than recommending a refund, they’ve suggested I send the unit to them for testing instead. At this point, it feels like they know this is simply how the device behaves and are unwilling to say so plainly.

My new drive: