Seagate 500GB External HD won't mount-help!

Ouch,

You mean Data rescue couldn't help?

Have you tried DiskWarrior?

Error = Unrecognized filesystem (-9958)

Your filesystem appears to be damaged beyond what Apple's Disk Utility is willing to repair.

Frankly it's insane to have one copy of 10 years worth of files you think are important, with that out of the way.

If you really need the data and want it back with the most likely chance of success of reading it all stop using it right now and contact a drive recovery company. They have the knowledge & expertise that could save data from a disk that may have a very limited amount of life left - sometimes falling disks will stop reading as physical damage gets worse. It will be expensive, but it's the best option they should have clean rooms for disassembling & checking it is operational. They may also know what different noises may mean - any abnormal sounds are clues to what the disk is doing (or not doing).

Another thing to consider – the external case or USB port, cable or power supply could be failing. Removing the disk & installing into another case may be a possible way to see the disks state. The age of the disk will dictate the type of case you need (SATA or ATA). Also see if another Mac mounts it - the OS could be failing not the disk.

These are the risks that your own attempts to recover or repair.

• Causing more damage to the HD until it becomes totally unreadable, running several recovery or repair tools may simply cause more damage.
• A physical failure can simply become fatal to the ability to read any data.
• Repair tools can cause files to be lost or can recover many duplicates of data without the file names or folder structure - it can make sorting them impossible or very time consuming.
• Risk damaging or altering all other connected disks … tools like photorec & testdisk are not forgiving of typo's you can easily be working with the wrong disk. Remove ALL the disks that are cannot afford to be lost (it sounds extreme, but you are already in a bad situation don't make it worse). Device names are confusing, verify twice before doing anything.
• You need another disk to recover data onto this needs to be larger than the 500GB drive - you will get duplicates & may need to 'image' the entire drive before attempting repairs on the image (to limit more damage to a mechanical issue). Several disks may actually be required. ddrescue is a free tool to image failing disks.
• Time is another important factor, recovery or repair can be very a slow process & should also not be rushed, spend time reading manuals & guides before using tools that are new to you. Also read other sites that discuss the tools.

It's unclear what the actual issue here is & what options you would like to take. You could just try every utility you can find, but that will cause the disk to die if it is having mechanical issues. You need to be methodical & log what info you have.

Are you really on a G4 Power Mac with 10.4.11? You will need older versions of tools like Disk Warrior to handle the disk format correctly, otherwise they may fail or cause other damage.

Have you checked with Seagate site to see if they support or a user support community that may help solve the problem?

I've heard good reports on it, but have never tried it.

Michael Brugh wrote:

Yes, I am really on a Power Mac G4 Mirror Door. I have been working diligently to get a more recent Mac. Don't worry, I have been chastising myself plenty over this situation. I used to be a Network Administrator for 10 years, so I know the importance of backups.

A data recovery company is the very last resort. I did download Stellar Phoenix Mac Data Recovery, v. 6.0.0.1. It does see the affected drive, and on the Search Lost/Deleted Volumes option, it shows the drive with this configuration:

Partition Type: GUID_partition_scheme

Bootable: Not bootable

Protocol: FireWire

Drive Capacity: 465.8 (GBBytes)

Ejectable: Yes

It gives me the option to Scan; however, before I click on it, I wanted to see if anyone has had success with this app. So many reviews out there; one says Data Rescue is best (didn't help), another says Tech Tool Pro is best, testdisk, photorec, etc.

The other disk you show in the Disk Utility output is an 'Apple partition map' not GUID. 10.4 does support both so your failed disk may be GUID, but I would double check via other tools. I would expect a PPC user to have more APM disks than GUID. Testdisk should give you info before offering to write out to disk.

I have found testdisk is good for fixing partition data & photorec is good for salvaging files (e.g. file carving, possibly without file names).

TechTool Pro ruined an OS disk for me several years ago, so I don't trust it. Disk Warrior has fixed disks for me numerous times.

Disk Drill may also be worth a look…

http://www.cleverfiles.com

I have only used it in free mode to do some test scans, never actually had the need for use in a real situation.

ddrescue may be an option if you want to do a clone to another disk to try to leave this one alone (if you suspect hardware that is dying). ddrescue will avoid retrying reading of bad sectors & can be run multiple times to pull data off a disk. You can attempt repairs on the clone & avoid worrying about too many mistakes. You can also 'clone the clone' to get several chances at recovery without touching the original disk more than one full read.

Have you had a good listen to the disk, does it sound OK?

Have you considered pulling it out of the case to see if it works via other drive interfaces?

Great info Drew, thanks, but just to clarify, 10.4 can only handle GUID if 10.4.11, not any earlier versions of 10.4 that I'm aware of anyway... a real problem if you have only a 10.4 Install Disc to repair drives with.

Cheers BDAqua, I couldn't remember which 10.4.xx added GUID support. I thought it was when the Intel Macs started shipping around the middle of 10.4.

Ah, you may be right on the Intel things, must be in fact, the first Mini Core Solo came with 10.4.5, the first Mac Pro with 10.4.7, so Machine specific Intel Discs are probably OK, not sure on Machine specific PPC Discs, I know the Retail 10.4 Discs I have won't handle GUID, only 10.4.11 on PPC I think is still valid, would be happy to be proved wrong though. 🙂

The site that is full of liars, scoundrels & some of the best people on the internet say 10.4.0 had support & 10.4.6 added features…

http://en.wikipedia.org/wiki/GUID_Partition_Table#UNIX_and_Unix-like_operating_s ystems

😝

Apples docs are linked…

https://developer.apple.com/library/mac/technotes/tn2166/_index.html

Apple's Support for GPT

Any Macintosh computer running Mac OS X 10.4 and later can mount GPT-partitioned disks.

…

On all Intel-based Macintosh computers (and, starting with Mac OS X 10.4.6, PowerPC-based computers as well), Disk Utility has full support for GPT. The

diskutil

command line tool also includes GPT support. See its man page for details.

The PPC manual is missing some GPT info though.

Very interesting, but now I'm more confused than ever! Tough my Retail Tiger Discs are all 10.4.3 I believe.

Ah, dern it, maybe it was Advanced Format I was thinking of that was only added in 10.4.11! 😊➖

one other thing - check the Console Logs (Utility menu-console option),

It may have additional reasons why its not mounting.

I thought that error meant that fsck had failed, however this (somewhat old) document suggests trying an fsck in single user mode…

Disk Utility reports "Underlying task reported failure" when repairing a volume - Apple Support

It may just be because Apple expect the user may be trying to fix the boot volume, fsck is best done when not mounted read+write.

There is some interesting info (also old) from Dale Weisshaar…

Underlying task reported failure on exit

See if you can find better info that is more recent - it sounds somewhat generic to me, the original "Error (-9958)" may find better info unless single user mode gives mode feedback. Do you know how to fsck the external in SU mode Michael?