WD Thunderbolt 8TB - Drive in slot b is missing

Hi all,

Every time I connect my external WD Thunderbolt drive (8TB RAID 1 mirrored) to my MacBook Pro (early 2013) I get a warning pop up saying the drive in slot b is missing.

I cannot be 100% but it feels to me that this has been happening since upgrading to Mac OS Sierra.

The drive is functioning fine with all the data there and accessible. If I open WD Drive Utilities and run the diagnosis tests everything passes successfully.

If the drive is on its way out how do I know when the tools say its fine?
If the drive is fine how do I get rid of the annoying (and thus incorrect) message?


Did try updating WD Drive Utilities for Mac after your system was updated? The application itself may be improperly reporting a missing drive as a result of needing to be updated.

Yeah, WD Drive Utilities is up-to-date

Should have said - that is the first thing I tried.

The tool says everything is fine.

The pop-up stating the problem appears without the tools running. What’s showing this dialog? Is that a WD Drive Utilities thing?

I have the same problem. It makes me feel impending doom every time I plug in the drive, but then it is working fine.