Mac Pro 5,1 - Disappearing Drive on Reboot

[John Doe 57]

I'm helping a friend upgrade his Mac Pro and we ran into an issue with a disappearing drive. There are a total of 4 drives plugged into the Mac Pro:

HD SLED 1: ORIGINAL APPLE 1TB HDD (BOOT DRIVE #1)
HD SLED 2: 860 EVO 2TB SSD
HD SLED 3: 4TB HGST NAS HDD
HD SLED 4: -EMPTY-

PCIe SLOT 1 X16: GTX 980 Ti 6GB
PCIe SLOT 2 X16: -EMPTY-
PCIe SLOT 3 X4: SONNET DUAL USB-C
PCIe SLOT 4 X4: SM951 512GB SSD (BOOT DRIVE #2)

When we select BOOT DRIVE #1 as the startup disk, everything works fine and the 4TB HGST appears. If we boot again (using BOOT DRIVE #1), the HGST is no where to be found. Disk Utility, System Profiler and the Terminal command "diskutil list" show no existence of the HGST. This same issue occurs when selecting BOOT DRIVE #2. For some reason, on a reboot the drive does not appear.

Anyone run into this issue before?

Mac Pro Specs:
Mid-2010 5,1
X5690 3.46GHz 6-Core
48GB 1333MHz DDR3 ECC
GTX 980 Ti 6GB

 

[crjackson2134]

I don’t know how to solve your problem but you’re not the only person to report similar when a 4GB+ drive is installed.

I’m not sure what the drive is used for, but you could pull it, and install it in a USB enclosure.

 

[John Doe 57]

you’re not the only person to report similar

Very interesting. Did some digging around and it looks like there's some more Terminal commands to try out and maybe even re-formatting using a different computer. Thanks for the heads up!