His 2020 Mac had served him well until it came back from a short absence changed. Working one day, he "went away for 4 days, came back and couldn't get past a folder icon with a '?' on it". The Apple Store's diagnosis was that "either the operating system or the hard drive is corrupt"; they "took out the hard drive and tried to put it in something else but it still didn't work", and handed it back. A flashing question-mark folder means the Mac cannot find a system to boot, and a drive that fails in a second machine too has a fault of its own — the store's cross-check already pointed at the drive rather than the computer.
| Media | Hard drive from a 2020 Mac, no longer responding — the Mac showing a flashing question-mark folder at boot, the drive also failing when connected to other hardware |
| Reported situation | Mac working normally, then unresponsive after four days off · flashing question-mark folder at startup · Apple diagnosing OS or drive corruption · drive tested in other hardware and still not working · drive returned to the owner · data recovery sought |
| Fault class | Drive-side failure confirmed by cross-hardware testing — the Mac unable to locate a bootable system, the drive not responding elsewhere either, consistent with a developing hardware or firmware fault; data behind it to be assessed |
| Equipment used | Drive assessed on PC-3000 UDMA — health, firmware state and responsiveness — since it fails across hardware · power draw profiled on a current-monitored bench supply · imaged under a hardware write-blocker on DeepSpar Disk Imager with head mapping where degraded, or firmware addressed where the fault is in the drive's own systems · Mac-native APFS/HFS+ read from the image in UFS Explorer, structures rebuilt · recovered files validated by rendering |
The question-mark folder is a specific message: no bootable system found. A Mac displays the flashing folder with a question mark when it cannot locate a valid operating system to start from. That happens when the system files cannot be read — because they are damaged, or because the drive holding them is not responding. It is the Mac reporting that its startup disk has become unreadable, not a random glitch.
The store's cross-hardware test is the diagnostic that matters, and it points at the drive. The most useful question with a non-booting machine is whether the fault is the computer or the drive. By removing the drive and trying it in something else — where it still did not work — the store established that the drive carries its fault with it. That rules out the Mac's other components and points squarely at the drive itself, which is exactly the right conclusion from that test.
"OS or hard drive corrupt" resolves toward the drive given that result. Apple offered two possibilities — corrupt operating system or corrupt drive — but a drive that also fails in other hardware is not a mere software problem, since a purely OS-level corruption would not stop the drive from working as storage elsewhere. The drive not responding across machines indicates a hardware or firmware fault in the drive, with the corruption a symptom rather than the root cause.
The route depends on where in the drive the fault sits, established at assessment. If the drive's media is degrading, retry-limited imaging secures the readable data first. If the fault is in the drive's firmware — its own internal systems — that is addressed on professional equipment to restore access before imaging. Either way the data is reached by getting the drive to a state where it can be read once, carefully, and imaged, rather than by repeated boot attempts.
The Mac context shapes the reading, and the prognosis is stated honestly. The volume is a Mac-native format read from the image with Apple-aware tools, not by plugging the bare drive into any machine. Whether the data comes back in full depends on the drive's specific fault and condition — assessed before the work, with a clear answer on what is recoverable before anything is charged.
The drive was assessed on PC-3000 UDMA for health, firmware state and responsiveness, and its power draw profiled on a current-monitored bench supply. It was imaged under a hardware write-blocker on DeepSpar Disk Imager with head mapping where degraded, or its firmware addressed where the fault lay in the drive's own systems. The Mac-native volume was read from the image in UFS Explorer, structures rebuilt, and the recovered files validated by rendering.
Drive-side fault assessed, the drive imaged or its firmware addressed as needed, and the Mac volume read from the image. The assessment is free and the quote is a single fixed figure inclusive of VAT; where a drive has to be opened, half of the parts and labour is payable up front and the balance falls due only on success — otherwise it is no recovery, no fee. The decode: the question-mark folder means the Mac found no system to boot, and the drive failing in other hardware proves the fault is the drive's. Reached properly and read from an image, your data comes back.
Stop repeatedly restarting it and don't reinstall the system or erase the drive — the question mark means no bootable system was found, often because the drive is failing, and reinstalling or erasing can overwrite recoverable data. If the drive also fails in other hardware, as here, the fault is the drive's, so no amount of software repair on the Mac will help. Set the drive aside and have it assessed and imaged, with the Mac volume read properly from a copy.
Our case files are written up from genuine enquiries our lab has handled for customers across Staines, Surrey and the surrounding area, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery approach our engineers apply to that fault, using the equipment listed.
Free diagnostic, fixed quote, no fix no fee — start now or call the freephone.