Trying to erase an old external Time Machine backup

[doctormelodious]

I have an external SATA drive that was a Time Machine backup for an old Mac. It lived in a Seagate Firewire enclosure which died. Suspecting that it was the Firewire circuitry that died (as seems to be the fate of many of these enclosures), I extricated it and installed it in another Mac. [EDIT: actually attached it, using an external docking station]

It does not mount. Disk Utility sees it, but my attempts to mount or erase it there failed. (I don't need the data; just want to wipe the disk.)

So I tried going the Terminal route, but still had no success. Here is the transcript of that session:

2021.04.09 09:17:06: diskutil list

[All of my regular disks showed here under disk0, disk1, disk2]

/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk3
1: EFI 209.7 MB disk3s1
2: Apple_HFS TM Backup 999.9 GB disk3s2

2021.04.09 09:17:09: diskutil mount disk3s2

Volume on disk3s2 timed out waiting to mount

2021.04.09 09:17:13: sudo diskutil reformat disk3

Password:

disk3 does not appear to have a valid file system format
Usage: diskutil reformat MountPoint|DiskIdentifier|DeviceNode
Completely erase an existing volume with the same name and format as the
original. Ownership of the affected disk is required.
You cannot erase the boot volume, nor can you reformat any device which
does not have a valid filesystem (instead use diskutil eraseVolume).

2021.04.09 09:18:52: diskutil eraseDisk JHFS+ Untitled /dev/disk3

Started erase on disk3

Unmounting disk [This went on for about a minute, displaying a series of moving slashes, then timed out. The thing is, there was nothing mounted to begin with.]

Error: 12: POSIX reports: Cannot allocate memory

2021.04.09 09:23:35: sudo diskutil eraseVolume JHFS+ Untitled /dev/disk3s2

Password:

Usage: diskutil eraseVolume format name MountPoint|DiskIdentifier|DeviceNode
Completely erase an existing volume. Ownership of the affected disk is
required. Format is the specific filesystem name you want to erase it as
(HFS+, etc.). Name is the (new) volume name (subject to filesystem naming
restrictions), or can be specified as %noformat% to skip initialization
(newfs). You cannot erase the boot volume.
Example: diskutil eraseVolume JHFS+ UntitledHFS /Volumes/SomeDisk

Any other ideas? Thanks.

 

[Fishrrman]

I would take the drive OUT OF the Mac (yes, I realize it's a job), put it into an EXTERNAL USB3/SATA docking station, and try to format it that way.

If disk utility won't erase it to HFS+ (which you should be using on a platter-based HDD), try exFAT.
If it will erase to exFAT, do that and then try AGAIN to re-erase it to HFS+.

 

[doctormelodious]

I would take the drive OUT OF the Mac (yes, I realize it's a job), put it into an EXTERNAL USB3/SATA docking station, and try to format it that way.

If disk utility won't erase it to HFS+ (which you should be using on a platter-based HDD), try exFAT.
If it will erase to exFAT, do that and then try AGAIN to re-erase it to HFS+.

I know I said that I "installed" it in another Mac, but I actually did use a docking station.

Just tried exFat. Still got the "Unmounting disk" with the moving slashes until it timed out. (I don't understand this, as nothing was mounted.) This time the error was "Error: 2: POSIX reports: No such file or directory" and when I did diskutil list again, disk3 was no longer there.

This has happened repeatedly after I've tried to do anything to it with Disk Utility or diskutil in Terminal. I disconnect the USB cable from my Mac, power the drive down and back up, reattach the USB cable, redo diskutil list and disk3 magically reappears, with its volumes intact.

I'm stumped. 🤔

Thanks for the reply!

 

[doctormelodious]

I know I said that I "installed" it in another Mac, but I actually did use a docking station.

Just tried exFat. Still got the "Unmounting disk" with the moving slashes until it timed out. (I don't understand this, as nothing was mounted.) This time the error was "Error: 2: POSIX reports: No such file or directory" and when I did diskutil list again, disk3 was no longer there.

This has happened repeatedly after I've tried to do anything to it with Disk Utility or diskutil in Terminal. I disconnect the USB cable from my Mac, power the drive down and back up, reattach the USB cable, redo diskutil list and disk3 magically reappears, with its volumes intact.

I'm stumped. 🤔

Thanks for the reply!

Oh, after that I did try HFS+ as you suggested. Same results.

 

[glenthompson]

If you don't need the drive or the data on it, I suggest an 8 pound sledge hammer. that will keep anyone from reading the data. It may not have been the Firewire enclosure that was the problem but the drive itself.

What I like to do with old drives is to disassemble them to get the magnets out. Very strong magnets and useful for a number of purposes.

 

[doctormelodious]

If you don't need the drive or the data on it, I suggest an 8 pound sledge hammer. that will keep anyone from reading the data. It may not have been the Firewire enclosure that was the problem but the drive itself.

What I like to do with old drives is to disassemble them to get the magnets out. Very strong magnets and useful for a number of purposes.

The sledge hammer option is definitely on my list! 😆

And yes, you may be right about the drive itself, rather than the enclosure, having been the culprit.

 

[Fishrrman]

Take the drive to a PC and see if it will erase on that.
Or... try a different enclosure/dock.