After Big Sur update, I can't mount my Drobo...

I'm answering my own questions in case anyone else has similar challenges with the 5D3. First, I'm not sure if use UBS-C to USB-A is what made the desktop icon correct (image of Drobo drive). Instead, it may be that when I restart the Mac it makes the drive a generic icon. Then I can unmount and mount it to get it to show the right drive icon.

I'm currently using the 5D3 with a USB-C to USB-A cable until Drobo releases the update to support me going back to the Thunderbolt connection. This USB connection is slower, but since the Drobo is just a backup drive, I don't care too much about that.

Now... The elusive problem with Drobo Dashboard not finding the drive (even the drive is fully functional in the OS). I tried everything. Uninstalled and reinstalled Drobo Dashboard (DD). Uninstalled DD and then manually removed any residual reference I could find to DD (ex. Full Disk Access under System Pref>Privacy). Nothing worked. However, I found a DroboTBT.kext file in Library/Staged Extensions/Library/Extensions. It took my a while to figure out how to delete that. The summary is: Disconnect Drobo from the Mac. Reboot to Recovery Mode. Use Terminal to execute 'csrutil disable'. Restart (normally). Delete the .kext file. Reboot to Recovery Mode. Terminal to execute 'csrutil enable'. Restart normal. Install Drobo Dashboard. Reconnect (for now, via USB). Open DD and it found the drive.

Drobo's FAQ page now notes that they are preparing to push out a 3.5.2 update to Drobo Dashboard that re-enables Thunderbolt support.

So between macOS 11.1 and DD 3.5.2, we should have Thunderbolt access back in the near future. Now hopefully the two play nice with each other.

It seems you can just follow the 3.5.1 link and change the applicable 1 to a 2: https://files.drobo.com/webrelease/dashboard/Drobo-Dashboard-3.5.2.dmg

This downloads a file but I don't know how to verify the version. I am going to wait until I see them make it officially available.

Thanks. I uninstalled and reinstalled with that link and now the thunderbolt works and my DD version says 3.5.2 but I am still having the same issue with all the lights solid red and it showing no data and no icon on my desktop and it showing up as Uninitialized on the disk utility. I think I will have to follow the steps previously posted by matt_lx again with an uninstall and removal of the .kext file then resinstall from the link just posted and see if it prompts me for a rebuild and go that way. I have not heard from Drobo tech support since the 19th which is annoying. I am thankful that you all are here with helpful answers.

kellyprn, That's great. I'm glad it was bricked. It will forever remain a mystery how the OS update corrupted the array. But at least the hardware is healthy and with the data transfer you should me made whole again.

Having same issue as @Kellyprn. MacBook Pro connected to two Drobo D5s via USB-C to Thunderbolt 2(?) then daisy chained one Drobo to the other. Installed 11.0.1 Big Sur, and latest Drobo dashboard 3.5.2. Dashboard was seeing both Drobos just fine but they were not mounting on desktop. Disk Utility also saw them but as generic name and said they were "uninitialized" and giving bogus disk size. I was too nervous to start tearing into terminal or reformat so I tried to swap cables first. I dug out an obscure USB-3b to USB-3a cable (thankfully I'm a cable pack rat) That worked, sort of. I could see the first Drobo in the dashboard and it mounted on the desktop but could not see the daisy chained 2nd Drobo - which was still daisy chained using Thunderbolt 2. So partial success. Seems its still a Thunderbolt issue? This at least gets me one drive up at a time. Not impressed with Drobo putting me through this mess.

UPDATE: Got the USB connection to work but only one of the drives at a time (only had one cable). Finally got Thunderbolt to work w/ daisy chained drives. Key for me was to uninstall the Drobo dashboard. But also to delete “DDService64d” file in Security & Privacy / Full Disk Access. Once I deleted that file and restarted, then reinstalled Drobo 3.5.2 dashboard. It then asked you several times to “allow” access under Security&Privacy. I restarted at least 2x and each time had to go into Privacy to approve a dialog box. On 3rd restart… disks finally showed up on desktop. ThanksGiving indeed !

I have downloaded and installed the Drobo Dashboard 3.5.2 update on macOS 11.0.1 and confirmed it does restore Thunderbolt connectivity.

what link? from the Drobo website? here? https://www.drobo.com/docs/

didn't for me

This really helped me! Thank you so much! My Drobo has mounted on the desktop!

THANK YOU!