statement from Rod Harrison, VP of Engineering at StorCentric, parent company of Drobo:
macOS Catalina has reported issues with multiple external devices from various manufacturers. We have reported this to Apple in regards to Drobo specifically and we are still awaiting an update from the company. We will share an update with all of our customers as soon as we receive this. However, as this is a broader issue across multiple external devices, we do not believe that this should prevent Drobo users from upgrading to Catalina.
This is why it’s good to let major OS updates get the bugs worked out before installing it.
More info here:
https://www.zdnet.com/article/macos-catalina-warning-dont-upgrade-if-you-rely-on-a-drobo-8d/