I have an 2nd gen 4-bay Drobo that won’t mount on any of my two Macs. It shows up in the Drobo dashboard. All lights are green. Fans are on. In Disk Utility (OS 10.11.3), the drives shows up as “Trusted Mass Storage Media”, but the option to Mount it is greyed out. Further, it shows the drive as “Unformatted”. First Aid claims there’s an Invalid Volume Header @ 17591842070016: unsupported format". I’ve tried a different USB cable and different ports. I’ve also tried it on my laptop and the behavior is the same. I’ve rebooted both the Drobo and machine as per the KB articles, with no luck. FSCK is not running on either Mac when the Drobo is attached.
I bought a copy of DiskWarrior 5- at the recommendation of several forum posts. It was an immediate dud. When I select the drive, it says this: “This is an offline, unavailable Core Storage Disk”. No amount of rebooting or recabling makes any difference.
What are my options?