Boot errors · explained

‘No bootable device found’ — what it actually means.

“No bootable device found.” It’s a heart-sink message to see on startup — but before you assume the worst, know this: your files are usually completely fine. The error means the computer can’t find something to start up from, which is a different thing from your data being gone. The cause ranges from a trivial setting to a failed drive, and telling them apart is the key.

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// in short

Your data is usually fine.

This is a boot problem, not a data problem. The error means the computer can’t start up — but your files are typically untouched. Don’t reinstall or format to ‘fix’ it before recovering them.

Boot
Not your data
BIOS
Is the drive listed?
Repairable
If it’s corruption
Never
Reinstall before recovering
// what it means

What the error means.

When a computer starts, it looks for a drive with a working operating system to boot from. “No bootable device found” — and its cousins, “operating system not found” and “boot device not found” — simply mean it couldn’t find one. That can happen for reasons ranging from harmless to serious, but the crucial reassurance is that it says nothing about your files.

Your documents, photos and everything else live as data on the drive, quite separately from the boot information the computer is looking for. So even when the machine won’t start, that data is usually sitting there intact — which shapes everything about how to respond.

// the key question

The question that decides it.

One check tells you which situation you’re in: go into the BIOS/UEFI (usually a key like F2, Del or Esc at power-on) and see whether the drive is listed. If the drive appears, the hardware is fine and the problem is the boot configuration — a setting or corrupted boot files. That’s repairable, and your data is safe.

If the drive doesn’t appear in the BIOS at all — especially if it’s also silent or clicking — that points to a drive that has failed or disconnected. That’s the serious case, and the data needs recovering rather than the boot repairing.

// easy causes

The easy causes.

If the drive shows in the BIOS, start with the simple fixes. Check the boot order — the BIOS may be trying to boot from the wrong device, and a USB stick or SD card left plugged in is a classic culprit; remove it and restart. If you’re comfortable inside a desktop, a loose SATA or power cable can drop an internal drive, and reseating it can bring it back.

These account for a good share of boot-device errors and cost nothing to try — a stray USB stick has fooled many a panicked user into thinking their drive had died.

// corrupt boot

When the boot files are corrupt.

If the drive is detected and the boot order is right, the boot files themselves may be corrupt — damaged by a bad update, a power cut during a write, or file-system corruption in the boot area. The drive is healthy and your data is fine; only the startup information is broken. Windows’ Startup Repair (from install or recovery media) can often fix it, as can boot-repair commands, and a Mac’s Recovery mode offers the equivalent.

Here’s the vital caution: don’t reinstall the operating system or format the drive to “fix” the error before you’ve got your data off. A clean install can wipe your files — solving the boot problem by destroying the very thing you were worried about.

// getting data off

Getting your data off.

If you can’t repair the boot but the drive is healthy, your files are still recoverable without booting the machine at all. You can connect the drive to another computer (or boot the affected machine from a USB) and copy your data off — on a normal, unencrypted, removable drive that’s often straightforward. Modern laptops with soldered, encrypted drives are the exception and may need specialist help.

The priority order is simple: recover your data first, fix the boot second. Never do it the other way round.

// drive failure

When it’s a failed drive.

If the drive isn’t detected in the BIOS, or it’s making noises, the boot error is a symptom of a drive that has failed — and no boot repair will help, because there’s nothing for the computer to talk to. Stop trying to boot, and don’t keep power-cycling; a failing drive needs recovery, not restarts.

Even then, the data is usually still on the drive — a failed drive is an access problem, not erased files — and can be recovered by repairing or imaging the drive. A diagnostic confirms whether you’re facing a boot fault or a drive fault.

// faq

Common questions.

What people ask us most about boot-device errors.

Almost never. The error means the computer can’t find an operating system to start from — it says nothing about your files, which live separately on the drive and are usually intact. The cause might be a boot setting, corrupt boot files, or a failed drive, but in every case except total drive destruction, your data is typically still recoverable.

Check the BIOS/UEFI and see whether the drive is listed. If it appears, the hardware is fine and the problem is the boot configuration or corrupt boot files — repairable, with your data safe. If the drive isn’t listed at all, or it’s making noises, the drive has likely failed, and the data needs recovering rather than the boot repairing.

Not before recovering your data. Reinstalling the operating system or formatting the drive can wipe your files — fixing the boot problem by destroying what you were trying to protect. If your data matters, get it off the drive first (by connecting it to another computer or using recovery), and only then repair or reinstall. Recover first, fix second.

// won’t boot?

Boot error with important files? Recover first.

Don’t reinstall or format to fix a boot error — that can wipe your data. If the drive isn’t detected or is making noises, send it in for a free diagnostic. Post it in from anywhere in the UK, or drop it to us in Belfast.

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