Mechanical — the moving parts
Head failure, head crash, jammed spindle, stiction. Clicking, grinding, scraping or buzzing without spinning. Requires matching donor parts. Deterioration occurs with every passing minute that the drive operates.
Urgent
Nearly every drive fault falls under one of four categories. The only thing all four categories share is the symptoms of why you're reading this. Two will deteriorate on a minute to minute basis when your drive is running. The other two will never deteriorate, and being able to identify which type you have will dictate how you should proceed for the next ten minutes.
Mechanical failures occur over time, with each operating hour contributing to their deterioration. Electronic/firmware failures are static. Therefore, if you are holding a mechanical failure, then the next ten minutes may be important. If you are holding an electronic/firmware failure, then those same ten minutes may not be important at all.
Which of these you have will determine the route, price, urgency and realistic probability. Thus it has to be established first.
Almost all faults with a hard drive fall into one of four groups. They are not variations on a theme. You can't access your files; that is the only thing a mechanical problem and a logical problem have in common.
While two of the four are going to become measurably worse during run-time, two will not. The difference by itself is worth knowing before you decide which course of action to pursue next, because for half of them the best use of time would be to stop.
Identified by the symptoms and if there is any urgency.
Head failure, head crash, jammed spindle, stiction. Clicking, grinding, scraping or buzzing without spinning. Requires matching donor parts. Deterioration occurs with every passing minute that the drive operates.
Surge, failed TVS protective diodes, ageing components. Silent and non-detectable drive. Mechanism and platter unharmed. More likely to have recovery options than some of the others. No deterioration occurring.
The drive spins as usual, sounds like normal operation and reports zero capacity or simply a blank model. Modules in the service area have become unreadable such that the drive cannot report its characteristics. However, user data typically exists undamaged behind the failed module.
Lost files, deleted partitions, formatted volumes, corrupted structure. The drive is functioning physically but the logical map to access your data has been damaged. Time is critical only in the sense that once you write over existing data on a disk, it will be overwritten, regardless of whether the disk is otherwise recoverable.
Most failures can be identified by yourself prior to notifying anyone and without cost.
Yes: It is mechanically failing, and it will get worse. Shut down now and stop powering it. None of the following tests are worth running as long as it continues to run.
Try to put your hand on the disk. A silent non-vibrating unit normally indicates there's something wrong with the electronic circuit board rather than the mechanical components of the drive – which is good news for you.
If a hard drive is absent in Windows but can be seen by the BIOS, then it is possibly a problem with the software/operating system, not hardware. It doesn't exist as far as both are concerned if it can't be seen at either level, which points at electronics or firmware.
A zero, blank model number, or what seems like an impossible amount is an indication of bad firmware. The drive is working properly and cannot describe itself.
It is logical if you've got a damaged file system or partition table and the data is still physically there. It was detected with unreadable or missing files.
Practical application of the classification, therefore the advice given varies quite significantly.
Mechanical damage compounds. When a head is flying at an incorrect height, it occasionally makes contact, when a head contacts a surface, it produces particles and those particles make contact again. When a particle causes additional contact there is more opportunity for damage. If the system is run continuously for 10 minutes after the first noise, it is entirely different from restarting the system each day for two weeks. The variation in time shows up in areas where nothing can be read.
Logical damage compounds too, but only if you write. Until deleted data is overwritten by another piece of data, deleted data remains. A running computer creates new pieces of data constantly (updates, cache, logs, index), which means the clock keeps running even though no user has requested anything. If the user stops using the computer then the clock effectively stops with it.
Electronic and firmware faults do not deteriorate. If the drive does not power on, it is not continuing to deteriorate while sitting in a drawer. Because there is no clock running for that particular drive, you now have enough time to determine what course of action to take regarding that drive.
In Manchester, a single drive is from £300 +VAT, regardless of whether it will ultimately turn into whatever class it ends up being, fixed in writing after a complimentary 48-hour diagnostic. The price does not increase based on how bad the diagnostic appears.
Four: mechanical (moving parts & noise announced), electronic (a failed circuit board, usually silent), firmware (the drive spins but can't describe itself), & logical (nothing is broken, just the map to your data was damaged).
Listen first. If it made any noise that it didn’t make previously, then it is mechanical – stop there. If not: quiet & unseen points towards a dead board; spinning but reporting zero capacity indicates firmware faults; mounting with missing files indicates logical faults.
Any mechanical damage will compound every minute the drive runs. However, any logical damage will only compound if something writes on the drive. Electronic and firmware faults do not compound at all – a dead drive sitting in a drawer is not getting worse.
Typically firmware. The operating code for drives is stored in a reserved service area on the platters. If a module becomes unreadable, the drive cannot describe itself so it reports nothing while making perfectly healthy sounds. Data is usually left intact.
Typically better. A silent drive without spin means something is wrong with the circuit board which leaves the platters & data alone. A clicking sound means there is an issue with the mechanism that will continue to deteriorate as long as it runs.
Not the initial cost — a single drive is from £300 plus VAT whichever class it is. What changes is whether a deposit applies. Donor part work costs a significant upfront cost. Therefore, all donor-part work requires 50% up-front payment with the remaining balance payable when successful.