h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Hi - I haven't visited here before. I'm a regular poster on the Archers message board, and Peet told me about this place a while ago. I currently have a problem which I'm not sure how to solve, and I'd be grateful for any advice you can offer.

I have a G4 Quicksilver tower, with 1.5GB RAM and two 80GB hard drives: one as the startup disc, and one as extra storage. It is running OS 10.4.11.

As on of the drives had been making a few odd noises in recent days, I decided to run Techtool 4.0.1 (http://www.micromat.com/index.php?option=com_content&task=view&id=31&Itemid=48 ). I started up my machine from the Techtool CD, and ran the check suite.

As part of this process, Techtool checked the directory structure. It found minor errors, and 'repaired' them, as the repair errors box was ticked. I remember hearing warnings about letting Norton Disk Doctor 'repair' the directory structure under OS X, but I thought that Techtool was safe.

After that, I could not start up from the hard drive. I eventually had to install OS X on the spare drive, and boot up from that, hence being able to post here. I ran Disc Utility. Disc utility lists both drives, but the volume name of the startup disc (eg Macintosh HD) is in grey rather than black. When I ran the Repair disc function, I got the following message:

Verify and Repair disk “Macintosh HD”
Checking HFS Plus volume.
Invalid B-tree node size
Volume check failed.

Error: The underlying task reported failure on exit

1 HFS volume checked
1 volume could not be repaired because of an error

The drive does not appear at all on the desktop, and I cannot access it from within the OS X environment, as far as I can tell, except by using Disc Utility.

Techtool is also able to detect the drive, but | cannot find any function within it from which I can recover the data. I used the Data recovery part, but this just whirred away for several hours with no indication as to what it was doing or whether it was going to be successful, so I stopped it. When I go in to the Wipe data function from the Techtool CD, this shows the drive and also provides a list of all the folders and files on it, looking in perfect order, but I want to recover them, not delete them.

I hope this gives you a reasonable picture of the state of play here. I know it was my own stupid fault for allowing Techtool to 'repair' the 'errors' it encountered, and for not backing up the drive before doing it. Fortunately I did back up my User folder a few weeks ago, but did not include the photos in that folder, and there are of course new emails etc which are on there since I backed it up.

Will I have to shell out for Alsoft's DiskWarrior to have any hope of recovering these data? I am on a very low income, so hope not, as it costs a fair whack. Or is there any other way of retrieving it or or repairing the Catalog B-tree?

Most grateful for any help you can provide.

thanks
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Well it's usually not a good sign when a hard drive makes odd noises. In my experience, that's the first sign of impending hardware failure - you're probably going to need a new hard drive. When you run Disk Utility, did you check the drive's "SMART" status? You need to click the icon for the drive hardware (not the formatted partition) to see the SMART status, if that says "failed" you definitely need a new drive. And I think DiskWarrior is much better at recovering files. If you can't afford to buy it, maybe someone you know who owns it will be willing to loan you a copy for a day? Or loan you the money to buy it? It's well worth having.

Ultimately, once you recover your files, you will *absolutely* need to erase and reformat that drive, but if you continue to hear odd noises after that buy yourself a new one as soon as you possibly can, and make frequent backups.

So yes, get DiskWarrior. There is something that is free, but I have never tried it and I don't know anyone who has used it on Mac OS X (but I do know people who used under Linux and even Windows), it's probably a "command line" utility that's difficult to use, I can NOT recommend it, but it may be worth a try if you think all is lost and can't get any worse - http://www.cgsecurity.org/wiki/TestDisk

Have you tried booting into single user mode and running FSCK on the dodgy drive?

Thanks to both of you for your time and replies.

I'm afraid I didn't understand a word of post 3 - "Have you tried booting into single user mode and running FSCK on the dodgy drive?" - is this something that would be worth me knowing about for the future, and if so would you mind explaining it?

In the end I got myself a copy of DiskWarrior 4. It's expensive, but it's more or less paid for itself by repairing the directory structure first time and making my system disc, and all my user data, usable again.

I think the noises I reported were a red herring: I only heard noises (like a chicken clucking very softly and contentedly) on and off for a few hours a week or so ago, and haven't heard anything since. I will get into the habit of performing more frequent back-ups.

Oh, and Techtool said that the SMART was in perfect working order; basically it told me the drive was fine, but rendered it unreadable in the process. I'm going to use DiskWarrior from now on.

all the best
'Ö'

I'm glad you got it working.

"Single User Mode" - you get to that by holding down command-s while starting up the computer. Frighteningly, you end up at the command-line shell prompt. You then need to type two commands (the message on the screnn tell you what they are, exactly), the second of which is "fsck" (File System ChecK), and it can repair your drive. Sometimes. I'm not sure it does anything differently than Disk Utility. Afterwards, you type "reboot" to restart the computer into normal mode.

Ah, thanks very much. I'll remember that.

All the best,
'Ö'