Thunderbolt Duo Problem

I have been running 2 units of MyBook Thunderbolt Duo side by side for nearly 4 years without any problems on my iMac. Both units are connected to both of my iMac’s thunderbolt slots directly and each unit has 2 removable disks, which are being striped with RAID 0 that gave me 6TB. All in all, I have 2 Thunderbolt duos, 4 Hard disks and 12TB of storage. Let’s now call this Thunderbolt Duo drives TD1 and TD2.

Recently, I have upgraded to Mojave and TD2 ejected by itself for no reason. When I rebooted it, it says that the drive A is missing. When I restarted it again, it says the RAID stripe set had failed. A later reboot tells me that drive B is missing. This error messages interchange whenever I reboot it.

Here is the strange thing. I had remove the 2 hard disks from TD2 - and place them in TD1. This drive rebooted without any issues with all my data intact. This means that there is absolutely nothing wrong with the hard disks. When I interchange the hard disks itself - TD2 behaves the same with the same error. What I don’t understand is, why did TD1 works and TD2 doesn’t? They are of the same configuration, same firmware and same hard disks - connected to the same iMac with same MacOS version.

I decided to replace the cables, alternate the ports on my iMac, switch the cables around and tried every possible combination. I just could not get TD2 to work properly again while TD1 works like a charm.

Can someone tell me what is going on with this Thunderbolt Duo Drive and how did I resolve it?

Hi kelvyim, are you still having problems?

I have a 12 TB My Book Duo (USB, not Thunderbolt) connected with a USB-C cable, and for the almost-a-year I’ve had it, it’s been problematic. I sent it in to WD once to be repaired or replaced and it continues to act up. I periodically get warnings about RAID configuration errors, then a day or two later Drive Genius reports an error, usually something serious. I run tests (always seems to pass), then every 2-3 months need to reformat the drive and start over from a Time Machine backup.

I did find this post that seemed to help, at least for a while. Error in RAID Configuration - #16 by bjcreative

I can’t locate the post now, but read somewhere on this forum that some WD software that’s still installed by WD is incompatible with several of the latest versions of macOS.

I recently re-installed my OS (Mojave) and deleted the offending WD software, and if the errors continue I will replace the with something other than a WD product. Similar issues have been happening to Mac users for over five years now, so I figure WD has had plenty of time to address it.

Best of luck!