# External HD not showing in Disk Utility



## rwinterborne (Nov 18, 2009)

I have an external hd that I removed from a user's Mac workstation (it was fully functional) and I want to attach it to the OSX server.  However, after attaching it to the server, I cannot see it in Disk Utility.  It does show up under System Profiler under the connection type.

I have tried USB and Firewire; I have rebooted the HD and the server.

Any thoughts?


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## VirtualTracy (Nov 18, 2009)

There are a few things we need to check:

Firstly I would test the hard drive on another Mac to see if it mounts correctly there. Also it's important to try a working drive on your computer to confirm that the USB or FireWire port on your Mac isn't defective.


On your Mac, make sure that _"Hard disks"_ under _"Show these items on the Desktop"_ is checked in Finder Preferences under _"Finder"_ in the menu at the top of your screen.
We need to determine exactly what the root of the problem is. Could it be a power supply-related issue? A cabling problem or a damaged hard drive itself? 


If the power indicator light doesn't come on or you don't hear the drive spinning, it could be a power issue. 

If the lights come on and the hard drive spins but doesn't mount on the desktop, then it could be a connection issue. Finally, if there is any unusual noise or silence, then it could very easily be the drive itself.

Check all the connections to confirm that they're seated correctly. This includes the power cable, both in the outlet and into the back of the drive. The same goes for the USB or FireWire cable; make sure it's connected firmly at both ends.

Test each component associated with the non-responsive hard drive on a working computer. Attach the drive to a different computer to see if it works and also use different cables and different ports on both computers. If your drive features both USB and FireWire ports, try both ports _(but not at the same time)_.
I know you have mentioned that the drive doesn't show in Disk Utility but I'm including this next step regardless:


Open _"Applications," "Utilities"_ and then _"Disk Utility"_ if the drive still doesn't respond. Disk Utility is Apple's program to help repair and mount damaged drives. If you're able to select the drive in the left-hand column, highlight it and click on _"Repair Disk"_ under the "First Aid" tab. If the disk doesn't appear in the list of available drives, quit Disk Utility, reboot the drive and launch Disk Utility again.

Try using a commercial disk utility package to attempt to repair the external drive or at least mount it so you can recover any data on the drive. _TechTool Pro,_ _DiskWarrior_ and _Drive Genius _are suitable. Every user has his own opinion of which is the best utility, but they all have the capability to get the job done.

Let us know how you get on


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## rwinterborne (Nov 19, 2009)

Thanks for the reply.  Here are more details on the issue:

I have two users who both use Mac workstations.  The external hard drive was attached to the Mac workstations and was fully functional - it was working correctly.  The issue was that only one of the users could access the drive at a time.

My intention is to attach the drive to the server and to share it out so both users can access it.  I plug the HD into the server via USB, and I can see it under System Profiler>USB but cannot see it in Disk Utility, and it doesn't auto mount to the desktop.  The same thing happens when I use a firewire cable.

So again, fully functional when attached to the Mac workstations; when attached to the server it doesn't auto mount or show in Disk Utility, but shows in System Profiler.  The drive is powered on, has power lights, works on other machines.  It seems like the issue is with the Server... but the only logical explanation is faulty ports.  I just dont see both the USB AND the firewire all going at the same time on a server that is only about a year or two old.


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## gsahli (Nov 19, 2009)

I guess you should be checking permissions.
in Terminal, do df to see if it's listed, then ls -alO /Volumes/


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## rwinterborne (Nov 19, 2009)

After going into Terminal and running the commands suggested, I see the following results... but still don't see the external drive?  I'm really at a loss here... I'm thinking it must be that the ports are bad.

Filesystem    512-blocks       Used Available Capacity  Mounted on
/dev/disk0s2   209715200   28503096 180700104    14%    /
devfs                221        221         0   100%    /dev
fdesc                  2          2         0   100%    /dev
/dev/disk3    1464477312  472811440 991665872    33%    /Volumes/Fileshare HD
/dev/disk0s3  1254500000 1060236632 194263368    85%    /Volumes/Time Machine HD
map -hosts             0          0         0   100%    /net
map auto_home          0          0         0   100%    /home
map -fstab             0          0         0   100%    /Network/Servers
debxserver:~ debadmin$ ls -alO /volumes/
total 8
drwxrwxrwt@  5 root      admin  hidden  170 Nov 17 16:08 .
drwxrwxr-t  35 root      admin  -      1258 Aug 18 23:57 ..
drwxrwxrwx+ 11 debadmin  staff  -       442 Oct 16 12:03 Fileshare HD
lrwxr-xr-x   1 root      admin  -         1 Nov 17 16:08 Macintosh HD -> /
drwxrwxr-x  10 root      admin  -       408 Jun 18  2008 Time Machine HD


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## gsahli (Nov 19, 2009)

I admit I'm no expert, but what I'd try is to re-mount the drive on the other computer and check permissions - owner and others, which groups they're in, etc. Then make sure that's compatible with the server.
To me it sounds like only the owner can access it. And the owner's group ID isn't on the server.


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## rwinterborne (Nov 20, 2009)

You are correct, the Mac User is the owner of this HD.  Now I need to change it, but how does one go about that?  Apologies, I'm no Mac guru...


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## gsahli (Nov 20, 2009)

Try this:
sudo chflags nouchg /Volumes/[name of the drive goes here]
then:
sudo chown root:storage /Volumes/[name of the drive goes here]
(This is an example of what I use - you have to first create the group storage, and add anyone to it that you want to have access to the disk)
(and you may need to add switches -Rf to make all subfolders obey the same permissions)

I'm Certain someone else here is more knowledgeable than me - hope they'll chime in to help.


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