manfredell, this obviously concerns us all, so please gve us some more details. This was with your DroboPro, on OSX – Leopard, or Snow Leopard?
Is there anything in the Mac’s log files that is indicative of something happening? When it happened before, was there an obvious cause, and how did you get around the problem?
I have seen something like that on my Drobo V2, where all of the directories were there, but no file contents. Fortunately, doing a power-off reboot brought them back to life with no damage.
When you shut down and restarted the Drobo, how did you do that? If you hanv’t already done so, I would try pulling the plug to absolutely force a reboot.
And finally, I assume that you have pulled diagnostics files and sent them in.
Please keep us all informed.