A business external that had become painfully slow, freezing whole machines when anyone opened anything from it. A local repair shop looked at it, recognised what it needed, and sent it on rather than attempting it — which was the right call and is worth saying so.
The drive held financial reports, client records and operational documents for a small business. It had been getting slower for weeks, then began freezing the computer entirely whenever anyone opened a folder from it, with Windows reporting read errors.
The repair shop diagnosed a failing drive, told the client honestly that it needed specialist equipment rather than another pass with software, and referred it on.
People almost always read this as the computer ageing, and it is worth explaining why it is not.
When a drive meets a sector it cannot read, it does not fail immediately. It retries — repositioning the head, waiting a full revolution for the sector to come round again, attempting error correction on progressively weaker signal — and a desktop-class drive will happily spend tens of seconds on a single sector before giving up.
The operating system has issued a read and simply waits. Nothing else happens on that machine while it does.
So a drive with a growing population of bad sectors presents as a computer that freezes for thirty seconds and then carries on as though nothing had happened. It reads as software bloat or an old machine. It is the disk telling you it is failing.
There is a mechanism here that explains why these drives deteriorate quietly for so long.
When a read fails, the drive marks that sector pending — suspected bad, but not yet condemned, because the drive cannot be certain the problem is the media rather than a one-off. It does not reallocate it there and then, because reallocating means writing the data elsewhere and the drive cannot read the data.
A pending sector is only resolved when something writes to it. Then the drive either succeeds and clears the flag, or fails and permanently remaps that address to a spare.
Which means a drive used mostly for reading never heals and never reports a growing reallocation count. The pending count climbs silently while the reallocated count stays flat, and anyone glancing at the headline figure sees a drive that looks fine.
Normal use touches a small fraction of a drive — the documents you are working on, last month’s photographs, the folders you actually visit. Vast regions go untouched for years, and those are precisely where unnoticed bad sectors accumulate.
Then something reads the whole thing: a migration, a full backup, an image taken before replacing a machine. For the first time in years the drive is asked for every sector, and the regions nobody visits turn out to be unreadable. The copy stalls, or the machine freezes, or Windows abandons the transfer.
It looks as though the migration broke the drive. It did not — it revealed a disk that had been deteriorating quietly while continuing to serve the small share of data anyone was actually using.
Which makes a full read a genuinely useful health check. If a drive will not give you a complete copy, you have learned something important while you still have options.
On a drive with spreading bad sectors this decides the outcome more than anything else, because the drive may not survive a complete pass.
A conventional clone starts at sector zero and works forward. If the drive dies two thirds of the way through, you have the first two thirds — which may or may not include anything the client cares about, since disk order has no relationship to importance.
So imaging ran differently. A fast first sweep with retries disabled captured everything that read on the first attempt, which is normally the large majority, securing the bulk within hours rather than days. Later passes returned to the gaps with longer timeouts, reading in both directions and resting the drive between sessions.
And the client’s accounts directory and current client files were located in the file system, translated to the physical regions holding them, and read explicitly first — so that had the drive failed partway, we would already have had what the business needed to keep trading.
The bad sectors were concentrated in bands rather than scattered evenly, which points at damage confined to specific surfaces rather than general wear — logical addresses are interleaved across heads, so damage to one head produces defects at a repeating stride rather than in one contiguous run.
The NTFS structures had been affected where they intersected those bands, which is what produced read errors and freezing rather than a clean failure. From the completed image the file system was rebuilt, with damaged records reconstructed from the backup copies NTFS maintains, and files verified by opening.
About 98%. The shortfall was files whose contents fell inside the damaged bands, identified individually by name so the client knew exactly what had not come back.
Worth crediting the shop. A repair business that recognises the line and refers a job on, rather than running a deep scan on failing hardware, has saved that customer a great deal. We work with several across Greater Manchester on exactly that basis. Single drives are from £300 +VAT after a free 48-hour diagnostic.
Send the device over with a short account of what happened to it. The diagnostic costs nothing and commits you to nothing, and the figure that follows is fixed in writing before anything is opened.
Nothing can begin until the device is on the bench, which makes this the only step that needs anything from you. Pack it properly, put your details in with it, and send it over. What follows is a free diagnostic and a written figure, in that order.
Posting it? Use something tracked and insured — whatever is on the drive is worth considerably more than the postage. Bringing it in? Weekdays, 9am to 5:30pm, and it still wants packing as above for the journey.
Tell us what the device is, what it is doing, and anything already tried — an engineer will come back with a realistic view of the odds and a price band, before you commit to posting anything.
We’ll be in touch shortly. For anything urgent, call 0161 871 0788.
Because the drive is retrying sectors it cannot read, which can take many seconds each, and the operating system waits. That is what a freeze followed by everything returning to normal usually means — not a slow computer, a failing disk.
Areas of the platter that can no longer be read reliably. They do spread — the counts only go up, never down — and once they begin appearing in numbers the drive is deteriorating rather than merely damaged.
If it still reads, yes, and you should do it now. Copy by importance rather than alphabetically, to a different physical drive. What you should not do is run a deep scan or a repair tool — those are hours of continuous reading on hardware that has limited reading left.
Because a failing drive may not survive a full pass. A fast first sweep banks everything that reads immediately, and later passes revisit only the gaps. Sequential cloning risks spending the drive’s remaining life on regions you did not need.
It is a good sign. A shop that recognises when a drive needs specialist imaging rather than another software attempt has protected your data. We take referrals from computer shops across Greater Manchester on that basis.
From £300 plus VAT for a single external drive, fixed in writing after a free 48-hour diagnostic, with most jobs no fix, no fee.
Start with an instant online quote, or call and talk it through with us first. You'll have a clear, fixed price before any work begins.