Data Recovery Case File · Portable Drives · One Look Settles It
There Is a Test for That, and It Costs Nothing
His enquiry names the fork precisely, which almost nobody does. A 2TB portable drive: "when plugged in the drive does not mount. The disk utility cannot repair it. I am unsure if this is a hardware or file corruption" problem. That is the question that determines everything — the cost, the method, the odds — and it can be answered in about ten seconds by looking at the right thing in the utility he already has open.
| Media | 2TB portable external hard drive with a Mac-native filesystem — not mounting; host repair utility unable to complete; fault class not established by the owner |
| Reported situation | Drive not mounting on connection · host disk utility unable to repair the volume · owner uncertain whether the fault is physical or logical · contents required |
| Fault class | To be distinguished by device enumeration — volume-level damage where the device presents with capacity; device-level failure where it does not |
| Equipment used | Device enumeration distinguished from volume mountability before any conclusion · no further repair attempts permitted · imaged write-blocked before any reconstruction · structures rebuilt from surviving copies on the image · files validated by opening |
The decode: the distinction, and how to see it
The test: in the disk utility, look at whether the device appears — the physical drive, with a manufacturer name and a capacity — as distinct from whether a mountable volume appears beneath it. Utilities list devices before they consider volumes, and they show disks they cannot read rather than hiding them, marking them as unreadable or greyed out.
If the device appears with its correct capacity: the hardware is doing its job. It powered up, completed its start-up, reported its identity and size, and answered the utility's questions. That is a working drive with a damaged volume — a logical fault, and the most recoverable category in this archive.
If nothing appears at all: the drive is not presenting itself as a device. That places the fault below the filesystem entirely — the drive never completed the introduction that would let anything address it. That is a hardware fault, and no repair, reformat or utility can reach it.
Why that one observation decides so much: a logical fault is addressed by imaging and rebuilding structures, and the prospects are generally good. A hardware fault requires the drive to be made readable first, which is a different kind of work with a different cost. Everything downstream depends on which side of that line he is on, and he can see it for himself.
What the failed repair tells us, and it is mildly encouraging: the utility attempted something and declined rather than completing badly. A repair that runs to completion on a damaged volume is worse than one that refuses, because it writes its conclusions over the structures a rebuild reads. His did not.
Why he must not try again: repair utilities are frequently offered with a "force" option or a suggestion to run it repeatedly. Each attempt writes, and each writes from information already partly altered.
The one thing worth adding whichever answer he gets: whether the drive spins and whether it makes any sound. A device that does not appear and is also silent is a different proposition from one that does not appear while clearly running — and both are hardware faults with quite different prospects.
On the bench
Device enumeration was distinguished from volume mountability before any conclusion — utilities listing physical devices before considering volumes and marking disks they cannot read rather than hiding them, so a device appearing with correct capacity indicates a working drive with a damaged volume, while nothing appearing places the fault below the filesystem entirely. No further repair attempts were permitted, a repair that completes on a damaged volume being worse than one that refuses. The drive was imaged write-blocked and structures rebuilt from their surviving copies on the image.
The outcome
Enumeration separated from mountability, no further repair permitted, and the structures rebuilt from the image. Free assessment, one fixed written figure including VAT; where a drive has to be opened, 50% of parts and labour is payable upfront with the balance only on success — otherwise no recovery, no fee. The decode: look at whether the device appears in the utility with its capacity, separately from whether a volume mounts. Device present means working hardware and a damaged volume. Nothing present means the drive never introduced itself, which is below the filesystem entirely.
Telling a hardware fault from a file system one
Open the disk utility and look at whether the physical device appears — with its manufacturer name and its capacity — separately from whether a mountable volume appears beneath it. Utilities list devices before they consider volumes, and they show disks they can't read rather than hiding them. If the device is there with the right capacity, your hardware powered up, completed its start-up and answered questions, so this is a damaged volume on a working drive, which is the most recoverable position there is. If nothing appears at all, the drive never introduced itself and the fault is below the filesystem where no utility can reach. Don't run the repair again either way.
Check whether the device appears — then call Guildford Data Recovery on 01483 901310; enumeration distinguished from mountability, imaged before any reconstruction, structures rebuilt from surviving copies.
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Our case files are drawn from genuine enquiries received by our laboratory over the past ten years, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery procedure our engineers apply to that fault, using the equipment listed.