Data Recovery Case File · Formatted & Logical Faults · Present but Unmounted

Drive Greyed Out in Disk Utility and Will Not Mount

Her enquiry compared two machines and reported one detail that most people never think to mention. A WD Passport for Mac: "Disk Utility can't see it, so I can't see or retrieve data. We have tried on another Mac that sees the drive in Disk Utility, but it is greyed out and unable to mount. The disk is spinning." Three observations, and together they are close to a complete diagnosis. The greyed-out state on the second Mac is not a failure message and not an error — it is a specific condition meaning macOS has found a volume and has not mounted it. That single fact places the fault above the hardware, and combined with the spinning and the difference between the two machines, it points at a job with a good outlook.

The decode: what greyed out means, and why two Macs differ

What the greyed-out entry is telling her: in Disk Utility, a volume shown in grey is one that exists and is not currently mounted. That is a precise state rather than a fault report, and it means a great deal has already succeeded: the drive received power, spun up, identified itself, and its partition structures were read well enough for macOS to know a volume is there and what it is called. What has not succeeded is the mount — because the filesystem's internal records are damaged or contradict one another, and macOS declines to mount an inconsistent filesystem rather than risk compounding the damage. So the failure is at the last stage of a long chain, and her files sit intact behind a catalogue that will not currently parse.

Why the spinning matters: it confirms the mechanical layer. The motor turns the platters, the bearings are fine, and the power delivery works — which eliminates the seized, stuck and dead-board categories that produce beeping or silence. Combined with the second Mac's greyed-out listing, the hardware is effectively acquitted.

Why the two Macs behave differently: less mysterious than it looks, and worth knowing. Disk Utility hides certain items unless Show All Devices is enabled in its View menu, so a drive can be present and simply not displayed. Different macOS versions also differ in how tolerant they are of structures they cannot parse — one may list a damaged volume and another may decline to show it at all. The difference is about presentation rather than about the drive being healthier on one machine, which is why the more informative result is the one that shows more.

The button that would make it worse: Disk Utility, having listed the volume, offers First Aid. It repairs filesystems by writing corrections — choosing between records that disagree, discarding entries it cannot reconcile, and moving orphaned data into recovery folders with generic names. On lightly inconsistent volumes it works; on badly damaged ones it converts something reconstructable into permanent structural loss and strips filenames in the process. There will also be an offer to mount, which is harmless, and possibly to erase, which is final. Reconstruction belongs on an image, where the same damage is examined with the whole picture available and nothing at risk.

On the bench

The drive was imaged write-blocked in one pass before any repair was contemplated — the discipline a repair utility fundamentally cannot offer, since everything afterwards happened against a copy and the original was never modified. On the image the structures were examined in order, the partition records first and then the filesystem, to establish which layer had failed and how far the damage extended. That layer was reconstructed until the volume mounted from the copy with its folder tree, filenames and dates intact, and signature carving swept alongside for anything beyond structural repair. Her files were verified by opening and delivered on fresh media.

The outcome

The volume rebuilt from a write-blocked image, verified and delivered. Free assessment, one fixed written figure including VAT, no recovery, no fee. The decode, for anyone facing a greyed-out volume: grey means present and unmounted rather than broken, so power, spin-up, identification and the partition structures have all succeeded and only the mount has failed — which puts your files intact behind a damaged catalogue; audible spinning confirms the mechanical layer is fine; and two Macs disagreeing usually reflects the Show All Devices setting and version differences rather than the drive behaving better on one. Decline First Aid, decline any offer to erase, and have the repair done on an image rather than on the only copy.

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.