Data Recovery Case File · Portable Drives · The Worst Sound
Grinding After a Knock: The Sound That Ends Attempts
His enquiry recorded the moment precisely and then, understandably, described everything he tried afterwards. A 2011 MacBook Pro: "it was in the middle of a restart, I threw my phone on the bed which knocked the edge of the laptop and it shut down again. Upon restart the drive has become unmountable. You can hear a grinding sound as if it is trying to boot up but cannot. I tried Disk Utility but it would not mount and First Aid did not work, nor did any of the other online recommended remedies. I bought data recovery software and an external hard drive to try and retrieve data, but it did not work." Two things need saying, and the first is urgent. Grinding is the one sound that means stop immediately — and every remedy he tried afterwards required the drive to run.
| Media | 2011 MacBook Pro internal hard drive — impact sustained during a restart cycle; volume unmountable; audible grinding on start-up attempts |
| Reported situation | Machine knocked while powered and restarting · drive unmountable since · grinding audible on each attempt · repair utilities and consumer recovery software subsequently run · multiple further power cycles applied |
| Fault class | Head-to-platter contact following impact while powered — surface damage progressive with every rotation; contact ongoing during all subsequent attempts |
| Equipment used | No power applied · laminar flow bench inspection of heads and platter surfaces first · scoring extent measured against intact area · matched donor head service · PC-3000 Express with Data Extractor prioritised imaging around damaged zones · losses reported per file |
The decode: why grinding is different, and what the attempts cost
What grinding means: the sounds a failing drive makes form a hierarchy, and this one sits at the top of it. Clicking is a head assembly failing to position itself — serious, and serviceable. Beeping is a motor unable to turn the platters — serious, and serviceable. Grinding or scraping is physical contact between the heads and the platter surface, and it is different in kind because it is destructive while it happens. A head touching a spinning platter removes the magnetic coating, and the coating is where the data is. Every second of rotation widens the damage, and scored areas are unrecoverable by anyone, at any price, permanently.
Why the knock caused it: the machine was restarting, which means the drive was powered and its heads were flying — not parked. A head in flight sits nanometres above a platter turning at thousands of revolutions per minute, and an impact at that moment can drive it into the surface. Had the laptop been switched off, the heads would have been parked clear on a ramp at the edge and the same knock would very likely have caused nothing at all. That single difference — powered or not — is the largest variable in every drop case in this archive.
What each subsequent attempt cost: said without reproach, because everything he did was reasonable and widely recommended. But every item on that list required the drive to spin. Restarting to hear the sound again: spinning. Disk Utility and First Aid: spinning, and First Aid additionally writes. Online remedies: spinning. Consumer recovery software scanning the drive: spinning continuously, for as long as the scan ran, across the entire surface — which on a drive making contact is the most damaging single thing on the list. He was not careless; he was doing what the internet advises, and the advice does not distinguish between a logical fault and a mechanical one.
What is still possible: genuinely useful, because grinding is not a verdict of total loss. Head contact is usually zonal — confined to the tracks the damaged head crossed — and material outside those zones frequently reads normally. So the honest deliverable is a map: the drive inspected before any power, serviced, and imaged with damaged regions deliberately deferred, with every unreadable area resolved to the specific files it affects. What determines how much survives is largely how many rotations occurred after the knock.
On the bench
The drive was not powered on arrival — with grinding reported, powering it to confirm the symptom would have cost data for information already supplied. It was opened under the laminar flow bench and the platter surfaces inspected first, the scoring located and measured against the intact area, so that the plan followed the findings rather than a hypothesis. Matched donor heads were fitted, and imaging ran on the PC-3000 Express under Data Extractor: head-mapped and prioritised, the healthy expanse captured completely before any damaged zone was approached, all in one supervised session. Every unreadable region was resolved to the files it affected.
The outcome
The surfaces inspected before power, the head assembly replaced and the readable area imaged in one supervised session, with the losses named per file. Free assessment, one fixed written figure including VAT, 50% of parts and labour upfront with the balance only on successful recovery. The decode, for anyone whose drive is grinding: that sound is head-to-platter contact, and unlike clicking or beeping it destroys data while it happens — so it is the one symptom that means stop now and never power it again; a knock while the machine was running is far worse than the same knock switched off, because flying heads have nowhere to go; and every remedy that involves the drive spinning — restarts, repair utilities, recovery software scans — costs more surface, with a full scan being the most expensive of all.
Drive making a grinding or scraping sound
Switch it off now and don't switch it on again — not to check, not to try one more thing, not to run a scan. Grinding is the heads touching the platters, which strips the magnetic coating that holds your data, and it gets worse every second the disk turns. That makes it different from clicking or beeping, which are serious but not actively destructive while you decide. It also means the standard advice you'll find online is actively harmful here: repair utilities, disk checks and recovery software all require the drive to spin, and a full surface scan is the most damaging thing you can run, because it drives the damaged head across the entire disk. None of that is obvious, and none of it is your fault. Take some encouragement too — contact damage is usually confined to zones, so material elsewhere often reads normally, and how much survives depends largely on how many rotations happened after the knock.
Stop everything now — call Glasgow Data Recovery on 0141 404 0294; surfaces inspected before any power, heads replaced with matched donor parts, imaged around the damage with losses named per file.
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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.