Drobo 5D not detected with drives installed

We had a Drobo 5D that was filled to near capacity. We replaced one of the drives with a higher capacity drive and let the Drobo rebuild. It completed. We then tried to replace another drive with a higher capacity drive. The process started but then the higher capacity drive apparently failed. We replaced it with another higher capacity drive and it appeared everything was working at first, but now the Drobo is no longer detected. We have tried connecting it to more than one computer (one running Windows and another a Mac laptop) to no avail. We have even tried connecting it to the Mac via thunderbolt and still nothing. The lights on the front of the Drobo are all flashing between green and orange indicating that it is rebuilding, but it has been this way for 7 days now.

We have tried the drives in another Drobo 5D. Same problem.

If we remove the drives and turn the Drobo on, Windows will detect it. Turn it off, put the drives in, turn it on, and now Windows will no longer detect it.

At a loss as to what to try next. Any ideas?

It may need a flush of the onboard system. If you have 2 spare HDDs, turn off you Drobo (I would even disconnect power and data leads to be sure), remove your current array (note the order), insert the 2 spare HDDs reconnect and turn it on again and hopefully the Drobo will be recognised and format those 2 drives. When completed and you can access the new volume, shut down and turn off the Drobo using the same procedure, take out the two drives and reinsert your previous drives in their original order, reconnect and restart.

Let us know if this solves your connection issues with your original array loaded?

Thank you. I will give this a try and let you know.


That did not work either.

The Drobo and the Windows machine seem to detect each other (e.g., the Drobo will go into standby mode if the computer is shutdown), and the Drobo detects all of the drives installed (green lights for the good drives and one red light for the empty bay), and the blue lights showing free space remaining are all lit up since there is no remaining free space now given the empty bay.

Still, the Drobo will not show up at all in the Drobo dashboard.

Could a failing Drobo have caused the problem? The Drobo now spontaneously shuts down and I am wondering if it failed during the rebuild. Could this have somehow caused an issue with the drives? No matter which Drobo 5D we move the drives to (we have tested this on three Drobo 5D units now), the Drobo we put the drives in is no longer detected by the Drobo dashboard. Take the drives out and the Drobo Dashboard will detect that Drobo. Put different drives in the Drobo and the Dashboard will detect that Drobo. Put the original drives back in and that Drobo and the Dashboard will not detect that Drobo anymore.

Appreciate any help. We have a lot of data on the drives that we want to recover.


This is not an advert.

I still use DiskWarrior on my Mac and in a similar circumstance when my Drobo 5D was not showing up on my Mac about 3 years back, DiscWarrior was able to recover and rebuilt the Drobo directory and I was working again.

The issue with DiskWarrior is that it is only compatible with previous Mac formatted disks but incompatible with the more recent MasOS’s, and APFS formatted HDDs so be aware if you want to pursue this route.


When DiskWarrior worked for you, was your Drobo being detected in the Drobo Dashboard or was it not being detected?


The Drobo was not visible in either the dashboard or as an icon on my Mac-mini.

I have a separate MacBook Pro that has purposely not been upgraded and it runs DW natively, and it ‘found’ my Drobo, then corrected its directory (HPFS+ formatted), thereafter the Drobo was accessible back on my Mac-mini.

The Drobo directory partially degrades (from the DW assessment) over time - the more you use it … etc., so I run DW every 3-4 months just to freshen then Drobo directory up. I will run Disc Utility once and awhile from the Mac-mini, but the DW has always found other issues. I also run DW before I upgrade any HDDs on my Drobo as a precaution. (Reading this back I come across a little paranoid!)

Anyway, hope this helps.

Thanks for the information, TwinTiger.

Our Drobo is formatted with the NTFS filesystem. It appears DiskWarrior only supports HFS/HFS+ based on the product website. Are there any DiskWarrior equivalent tools you would recommend for a Drobo formatted with NTFS?

That’s where my limited knowledge base ends I’m afraid. We are a many decades Mac household. Perhaps a MS Window’s forum may be able to give you some better guidance on NTFS directory rebuilds?