I have an external hard drive (Drobo 2nd gen) connected to my Mac via Firewire. It used to appear on my desktop and in my Finder sidebar, but now it won't show up in either place (I do have 'Hard disks' and 'External disks' turned on in the Finder sidebar options). The drive does seem to be mounting fine: the drive and partition are visible in Disk Utility and I can browse to it in Finder if I use the Finder's 'Go to Folder.' Command and type /Volumes/Drobo/. I can read/write to it fine once I've navigated to it. I have the latest version of Drobo's Dashboard utility installed, and my firmware is up to date. Is this a sign that my external drive is starting to die?

EDIT: I've resolved this problem with the help of Drobo's tech support. See my own accepted answer below. I've revised this answer to make it less Drobo-specific, since it ended up being a filesystem thing. With the help of Drobo's technical support who pointed me to, I've resolved the issue. It turned out that somehow my drive got set to 'invisible', which is a filesystem attribute.

I don't think this setting is settable via the Finder, so I'm not sure how it got set like that. To confirm the issue, I had to install and then install the command line tools, then run this Terminal command: GetFileInfo /Volumes/Drobo/ where /Volumes/Drobo/ is the path to the volume in question. This command returns all the attributes set for that volume. If the list of attributes includes a V (capital V), it means that the volume is invisible. To fix it: SetFile -a v /Volumes/Drobo/ with a lowercase v, to remove the invisible attribute. After a reboot, everything was back to normal.

Note: depending on the drive and your permissions, it's possible you will need to run these commands with sudo, although I didn't. Since the storage works just fine, it's more likely a problem with the software and/or a mismatch between your drobo software and the firmware on the device than it is a problem with the hardware.

Have you - specifically making sure you have no firewall ( or something else like Little Snitch). It's always possible that the portion of the Drobo that should be sending your Mac information has failed, but that's not as easy to fix other than attempting to re-flash the firmware. I'd personally open a support ticket with Drobo to be sure you are getting the best advice before flashing the HW. Also, when OS X mounts a new drive, it will check the filesystem and since Drobo reports such a huge size, this could take a very long time before the icon shows up.

I've seen this take more than 24 hours - expecially when the Drobo software doesn't see the device or is having issues helping drobo's filesystem get mounted in a timely manner.

Hey everyone. I wanted to put my experience here so that people could chip in and learn/share. For the past five months I had been having with my Drobo (2nd Gen with 2 FW800s and USB 2.0). It came bundled with 2x 1 TB WD drives. I set it up using Drobo Dashboard and for a time, everything was good in my data world. Then two things happened around the same time: Added a 1.5 TB drive to my Drobo and I added a password to secure disks for my Time Machine.

Shortly after my computer was no longer able to access my Drobo data via Finder. Drobo Dashboard would still report to me on it's status.

Aperture would save the vaults, iTunes would play music from the drive but I could not access the data through Finder, only with Terminal was I able to move, copy, and open/delete files. So what should I do but I try different cables, I try both FW ports on the Drobo and even resort to using USB from the Drobo to my computer. Issue remains. So I figure what the heck and I plug my Drobo via USB into my Time Capsule, it had worked before for me so let's see. I could see the files in folder. But wait,.!?

I move from the Drobo Directory back to my user directory and try to go back and I can't. It shows me that horrible site of the Drobo just as bad Alias. Double clicking it has Finder offer to fix the alias but alas that doesn't work just like I knew it wouldn't. I unmount the Drobo and retry going to NetworkTime Capsule Drobo and BAM! Finder sees the files again, but I change directories and hit 'Back' and now the Drobo is a bad alias again. This is starting to agitate me but being comfy with unix I survive, every day I hate plugging in the Drobo because I won't have that GUI-ease any more.

Months pass and having contacted Drobo, Apple, tech-savy friends I get nowhere. Then one day I try plugging my Drobo into my PowerMac G4 and the Drobo works fine there. (This is where I should've gotten my first clue). So I try to have my MBP access the Drobo through Network PMG4Drobo and 'Hooray' it is there again. But I am still not out getting beers of celebration. So I change directories and go back and darn I have the same alias issue. So now I see that my MBP can access the files via a Network connection 'one-time only' and other than that my other system works fine with it.

My cousin brings his MBP over and we test it out, it is perfect on his system. He can access the files, change directories from Drobo to his system and back again all day long, it is perfect.

This is puzzling me to no end. I talk to one of my great friends who has the in with all issues with the 'good' companies.

He mentions a possible bad Symlink and that gives me fuel to start my hunt for a resolution. Months go by and I get no where. This is destroying my tech-esteem, myself who is a AASP server guy and general S.M.A.R.T.-@$$. So I reach out again to my pals in various tech fields and no progress is made other than I learn a few more terminal commands. Well two weeks ago I say, 'screw it!'

And I start copying my Drobo data off to my other drives and spend the following 5 days copying things via Terminal from the Drobo to 3 different drives. At one point of the copy I tell terminal to 'sudo cp -rfv /Volumes/Drobo /Volumes/Extra Drive ' and you won't guess what happened within 30 seconds I was not able to access that drive via Finder though Terminal was still copying data just fine. So I stopped Terminal with Cmd+.

Drobo 2nd Gen Help For Mac Pro

And removed the invisible files that it had copied and then the Drive was good again in Finder. So changed my cp command and only did the two visible folders that mattered to me. Finder was still happy. (HINT!) I finally have my Drobo empty and things set aside and I figure that this time I won't use Drobo Dashboard to format it. So I go over to Disk Utility to reformat it. So this is where I get lucky and hit myself in the head because it never dawned on me to think about the limit of the Apple Partition Map (2 TBs). I knew a long time ago that APM didn't like being formatted for more than 1 TB and 2 TB was out of the question.

So I have Disk Utility reformat the drive for GUID. It works but there is a problem, Drobo Dashboard says that data is still on the Drobo.

Okay Drobo Dashboard, I'll play your game. So I go through the set up assistant and figure out what happened (maybe).

I think what originally happened is when I got the Drobo I set it up to be a 1 TB volume so Drobo Dashboard just set it to APM by default. So when I added the other 1.5 TB drive in months later, rather than just making that 1.5 drive a 1 TB image drive it went crazy with it and went halfway with APM and GUID structures. I say it that way because since it was my MBP that was plugged in with the Drobo originally the Symlink between my Drobo and MBP was different that other peoples units. So I took a second and revisited Drobo's latest updates and manuals and so I set up my Drobo to be 16 TBs in size though it has only 2x 1 TB and a 1.5 TB drive. Drobo Dashboard set up the unit to be GUID, erased the ghost data that had lingered from Disk Utility and things were fine.

Finder was finally working again so I copied over my system's User folder to the Drobo and it worked fine, navigation was GUI again and for 30 minutes I tested everything. I hope that with this out there other people can learn from my time and trials.

Please don't hesitate to comment or question me. I'd be happy to help and/or go into more detail. Quick side note though. Drobo should've seen this at the very get go had they asked better questions and actually looked at the screen shots I submitted to them of Finder, Drobo Dashboard, Disk Utility and more. The fact that Drobo doesn't give you the APM/GUID option during the walk through (and them smartly disabling it for people who go over 2 TBs is stupid on their part as well IMO). Thanks for reading and good luck to you and your data! Message was edited by: xgenius.

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