Drobo 5D - Won't connect via USB except on boot / Slow reconnect

I have been using my Drobo 5D for years via Thunderbolt however a bit of a story has me unable to use the Thunderbolt port reliably on my Macbook any more. Thus I am a first time use of the USB connection and am finding it is not nearly working like the Thunderbolt.

Firstly, it seems like my Macbook will only find and thus mount the Drobo during boot, if I connect the USB cable a bit later it does not list the USB device in ioreg and then for sure will not mount it.

Last night it may have connected after a long wait, or I was over tired and didn’t pay attention and need to do more testing. But it definitely does not within 5 minutes. If I boot with the USB attached the device and drives are great.

The scenario also happens if I disconnect the USB device (either safely or by accident), I am not able to get things back without a reboot, no USB device seems to be found/list after plugging it back in.

Latest firmware and latest OSX.

Just a thought
Is Drobo Dashboard still running after you disconnect your USB Drobo connection? If so, try exiting the Dashboard before you reconnect.

Tried that, unfortunately it did not seem to help.

I’ve since moved this over to a Windows machine and its been working great.