If your MacBook has not come back up after a macOS update, the most useful thing you can do right now is very little. Put it on mains power, leave it alone for a while, and find out whether you are looking at software or at hardware before you touch anything else.
In most failed-update cases the files are still sitting on the disk, untouched. What loses them is the next hour of well-meaning fixes: erasing in Disk Utility, reinstalling over the top, running First Aid again and again because the first run did not help. Below is what actually happens during an update, how to tell a stalled installer from failing hardware, and where the line sits between what you can safely do at home and what needs a laboratory.
Stop, and do these three things first
1. Connect the original charger and wait. A progress bar that appears frozen is often an installer still working through a large firmware or system step, and some updates genuinely take a couple of hours on older hardware. An update that runs out of battery halfway through a write is a far worse problem than an update that is simply slow. Give it at least two hours on mains power before you conclude anything.
2. Write down exactly what you see. This single detail decides everything that follows. Is there an Apple logo with a bar that still creeps forward? A bar frozen at the same point for hours? A circle with a line through it? A folder with a question mark? A black screen with the fans audible? Photograph it. When you describe the fault to anyone later, that picture is worth more than any description.
3. Force restart once. Once. Hold the power button for about ten seconds, release, then press it again. If the Mac returns to the same stall, stop there. Repeatedly cutting power to a machine that may be mid-write is one of the more reliable ways to turn a recoverable situation into an unrecoverable one.
Then leave Disk Utility alone until you have read the rest of this page.
What a macOS update actually does to your disk
Modern macOS does not keep your system and your files in one place. Your internal storage holds an APFS volume group made of two parts: a sealed, read-only System volume, and a separate Data volume that holds your documents, photos, desktop, mail, user accounts and application data.
An update does not rewrite the Data volume. It builds a fresh sealed System volume, verifies its cryptographic seal, and then points the machine at the new one to start from. Your files sit on the other side of that boundary the whole time.
That is why the MacBook will not boot and my data is gone are usually two different statements. A seal that fails verification, a firmware step interrupted by a power cut, a new system volume that never got marked as the startup volume — each of these stops the machine booting while every one of your files remains intact one volume across.
There is a less comfortable side to this. An update is also the heaviest sustained read and write your drive has been asked to do in months. Storage that was already weakening often gives up during one. The update did not cause the failure; it revealed it. Telling those two situations apart is the next job.
Failed update, or failed hardware?
The symptom on screen narrows it down quickly.
| What you see | What it usually means |
|---|---|
| Progress bar moves, stalls near the end, gets further after one restart | Installer problem. Data almost certainly intact |
| Apple logo, then a circle with a line through it | The system volume is not bootable. The Data volume is usually fine |
| Folder with a flashing question mark | No startup volume found. Could be software or storage |
| Recovery loads and Disk Utility lists the internal disk and Data volume | Software. Your files are still there |
| Recovery loads but no internal disk is listed at all | Storage or logic board. Serious |
| Restarts or panics a few seconds after the logo, repeatedly | Either. Stop and get it assessed |
| No power, no display, unusual heat, burning smell, liquid or a drop | Hardware. Stop immediately, do not keep powering it on |
The most informative safe test is booting to Recovery and opening Disk Utility with Show All Devices switched on in the View menu. If the internal container and the Data volume are listed, your files are very likely still present. Look, note what you see, and close it. Do not click anything that changes the disk.
Apple silicon, T2, and the soldered encrypted SSD
On every Apple silicon MacBook and every Intel Mac fitted with a T2 chip, roughly 2018 onwards, the flash storage holding your data is soldered to the logic board and encrypted at rest by default, whether or not you switched FileVault on. The keys live in the Secure Enclave on that same board and never leave it.
Three consequences worth being plain about:
- There is no drive to unscrew and read in another machine. On these models the storage, the controller and the board are effectively one component.
- Nobody can read that flash without the machine's own Secure Enclave. Reading the memory chips directly returns encrypted blocks and nothing legible. If FileVault was enabled, your own password or recovery key is needed on top of that. We say the same thing to every caller: we do not bypass encryption, passcodes or account security, and no laboratory can. Anyone promising otherwise is not telling you the truth.
- Where recovery is possible, it works through the board itself. Board-level work is done only to bring the storage to a state where it can be read and imaged. You receive your recovered files, not a repaired laptop.
Older Intel MacBooks, broadly 2017 and earlier, are a different situation. Many use a removable blade SSD or a standard drive that can be read on a bench like any other SSD, provided FileVault was not turned on. So the year of your Mac shapes your options more than the symptom does. Our Mac data recovery page sets out how each generation is handled.
What not to do (this is the part that costs people their files)
- Do not erase anything in Disk Utility. Recovery puts the Erase button directly in front of a stressed person. Erasing an APFS container on a soldered, encrypted SSD discards the volume keys, and that is genuinely final regardless of who you take it to afterwards.
- Do not reinstall macOS over the top while the files still matter. A standard reinstall is designed to leave the Data volume alone and usually does. But it writes many gigabytes onto a disk that may be failing, it consumes the free space where deleted files still live, and if the installer judges the container unhealthy it may offer to erase it. Get the data off first, reinstall second. Always in that order.
- Do not run First Aid repeatedly. First Aid is not a read-only check. It writes repairs to the filesystem structures. Once on healthy hardware is reasonable. Run after run on a drive that is failing can overwrite the very metadata a laboratory would otherwise use to rebuild your folder structure.
- Do not use Erase Mac, or a DFU restore in Apple Configurator. A restore erases the machine. Working out under pressure which option preserves data and which does not is exactly how people lose everything.
- Do not keep scanning the internal disk with recovery software while booted from that same disk. Every write reduces what can still be retrieved, the same principle that applies to any deleted file recovery job.
- Do not keep power-cycling a machine that is unusually hot, smells wrong, has been near liquid or has visible damage.
Safe ways to get your files off yourself
Check what you already have. Time Machine, iCloud Drive with Desktop and Documents syncing, or a clone on an external disk. Verify the backup by opening a few real files on another machine before you touch the MacBook further. Restoring from your own backup beats every other option here.
Try disk sharing or target disk mode. On Apple silicon, shut down, hold the power button until Options appears, then choose Utilities and Share Disk. Connect a data-capable Thunderbolt or USB-C cable to a second Mac and connect from its Finder, using an administrator password from the affected machine. On older Intel Macs, hold the T key at startup for target disk mode. Neither writes to your system volume. If the Data volume mounts on the other Mac, copy the irreplaceable folders first: documents, the photos library, desktop, mail.
One rule while copying. If reads are unusually slow, the second Mac hangs, or a copy fails partway through, stop. That is the point at which further attempts start costing you files rather than retrieving them. Copying from failing storage is a race, and each retry shortens the runway.
Once your data is safely on a healthy external drive, you can reinstall, restore or take the machine anywhere without risk. Keep two copies, not one.
macOS 27, the Intel deadline, and when to bring it to a lab
Apple has confirmed that macOS 26 Tahoe is the last release to support Intel Macs, which makes macOS 27 the first Apple-silicon-only version of macOS. Intel MachBooks will keep running and will receive security updates for a period, but anyone who needs current software now has a migration on the calendar. Over the coming year a great many people in Singapore will be moving from an Intel MacBook to an Apple silicon one.
Migrations are when data gets lost. The pattern is always the same. The old machine is wiped or sold before anyone confirms the transfer actually completed. Migration Assistant is run across a drive that was already showing early signs of trouble. A temporary backup disk quietly becomes the only copy for three weeks. A photos library is moved rather than copied. None of that is carelessness; it is simply what happens when two machines are in play and one of them is on its way out.
Sensible rules: have two copies before you start, verify by opening files rather than by watching a progress bar, and do not wipe the old Mac until the new one has been in daily use for a fortnight.
Bring the machine to a laboratory when the internal disk or Data volume does not appear in Recovery, when power was lost mid-update and the disk has not been seen since, when copying fails partway or the Mac freezes while reading, when there has been liquid or a drop, or simply when what is on it matters more than the machine does.
At CBL, bring the whole laptop and its charger, since on Apple silicon the board is the drive. Diagnosis is free and you receive a fixed written quote before any work begins. You see the list of recovered files and confirm it before you pay, and standard cases are handled on a no recovery, no fee basis. Everything is done in our own Singapore laboratory with an in-house cleanroom, so nothing is sent overseas. Data is handled in line with the PDPA and NDAs are available on request. If you want a sense of numbers first, see data recovery cost, or send us the details through the contact form and describe exactly what is on the screen.