Back-up / Retrieve Files from an external hard drive that doesn't appear in Devices

Get Disk Warrior that will repair the problems without requiring that you reformat the drive - $99.00 on a bootable CD. Will not work on a FAT formatted drive.

You will need to use Drag and Drop to save your files by copying them from the bad drive to a good one.

To reprep the drive:

Drive Preparation

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed.

4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.

5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.

6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.

Whilst Disk Warrior is your best and only hope, in most cases your data is lost.

No time to think about how you have all your life's savings stashed under the mattress when the house is on fire. You should have put it in the bank. You say how vital this is to you but you never even made copies back to DVD?

In the case of vital work on a computer that means full back-up to an exteranl hard drive/s, preferable kept separate from the originals location. Time Machine will make that dead easy for you and there are plenty of other backup solutions.

All the rest is regret and wishful thinking.

Peter

You are going to need version 4.x.

Do not use DW 3, don't use Apple Disk Utility either, unless it is suitable and certified for the OS you have, and DW 4.4 is what is needed for current Mac OS.

Never live without bootable clone of your OS.

Carbon Copy Cloner for OS X

Cloning as a Backup Strategy

Where did you get DW? You should have purchased 4.4 at Disk Warrior website. They no longer sell 3.x on their website.

No. DW doesn't recover files. DW fixes directory corruption that cannot be repaired by Disk Utility.

Yes, I suggest you do your file backups first if possible as a precaution. Otherwise, you will need to first repair the drive then make a full disk backup for future use.

Disk Warrior has an FAQ on Alsoft

The program has a Preview Mode for mounting current and "repaired" view of the disk.

Some drives are bad enough that the system could not boot with the drive powered on, and could not be mounted and it has a feature to allow mounting ("D")

READ. FIRST.

There is feature to Option+Click on "Rebuild" that will do a more thorough deeper scan of files and bypass the directory.

A severely corrupt disk directory can take hours, and in rare cases even go for couple days (good to have a UPS no matter what but especially now).

It is always best to have backup copies and sets. The old ounce of prevention vs pound of cure.

Do not INSTALL Disk Warrior or any other Utility if you ever want to see your data again. You need to boot from another drive or the DVD, and run the Utiity from there, and that is another reason you need the right version.

The disk blocks needed to Install the program will be taken from the free list on the wounded drive. At this point, you do not trust the free list not to contain Vital parts of your data. So do not Install anything onto that drive.

Some utilities take this to even more extremes. Data Rescue, for example, refuses to recover anything to the same drive or fix the directory. You need to provide it with an additional drive, and anything recovered will go to the new drive.

DW won't even run from the active startup volume except to repair a different drive. It is not a file recovery utility, just a directory repair utility.

You start up Disk Warrior and ask it to rebuild the troubled drive. Disk Warrior searches the existing directory, and where the directory blocks should be, and tries to find things that look like directory fragments, and builds a new tentative directory for your approval. Nothing has been changed yet.

It then shows a summary list of differences between the damaged file system and the one it has compiled, and tells you whether files would be gained or lost and what other consequences of installing the tentative directory would be. You can ask for a detailed list if you like. You can also view your drive using existing and tentative directory, side-by-side. Nothing has been changed yet.

Only AFTER you decide that the new tentative directory is better than the old, does it modify anything.