Something is plugged in
A USB stick, an SD card, a phone in file-transfer mode, an external drive. The firmware tried to boot from it, found nothing, and stopped. Unplug everything and try again — genuinely the commonest cause.
Try first
By the time this message appears, the machine has powered up, passed its self-test and reached the firmware. Only the last step failed. And boot files occupy a few hundred megabytes — everything you actually care about sits elsewhere on the disk, unaffected.
About half the time the disk is entirely healthy and something about where the firmware was told to look has changed. The other half it is failing — and the BIOS will usually tell you which.
Which is a narrower statement than it appears, and frequently a much less serious one.
By the time this message appears, quite a lot has already gone right. The machine powered up, passed its self-test, initialised memory and graphics, reached the firmware, and went looking for something to boot from. All of that worked.
What failed is the last step: nothing it checked contained a usable boot loader. That could mean the drive has died. It could equally mean the boot order changed, a cable worked loose, a USB stick was left in, or the boot files were damaged on a drive that is otherwise perfectly healthy.
The important consequence: this message says nothing about your files. Boot files occupy a few hundred megabytes at most. Documents, photographs and everything else sit elsewhere on the disk, entirely unaffected by whether the machine can start.
In the order worth checking, which is roughly the order of likelihood.
A USB stick, an SD card, a phone in file-transfer mode, an external drive. The firmware tried to boot from it, found nothing, and stopped. Unplug everything and try again — genuinely the commonest cause.
After a BIOS update, a CMOS battery failure, or a firmware reset. The drive is present and healthy; the machine is simply looking somewhere else first. Check the boot menu.
A failed Windows update, an interrupted shutdown, a partition resize that did not complete. The drive is fine and its data intact — only the small structures that start the operating system are broken.
Genuinely gone, or gone far enough that the firmware cannot read the boot sector. If the drive is absent from the BIOS entirely, or making noise, this is where you are.
None of these write to the drive.
Sticks, cards, phones, external drives, even some printers. Then power on. If it boots, that was the whole problem.
Usually F2, F12, Delete or Escape during startup. The question is simply whether the drive is listed. That single fact splits everything that follows.
It is present and communicating, so the hardware is fine. Set it as the first boot device and try again.
Absent from the BIOS means the machine cannot see it at all — a connection, controller or drive fault. Do not run repair tools, because there is nothing for them to repair.
If the machine is making a noise it did not make before, none of the above matters. Power it off and skip to the last section.
The point people miss, and it is often the whole answer.
Booting and reading are different things. Where the drive still functions, your files can be reached without the machine ever starting: take the drive out and connect it to another computer with a cheap USB adapter, or boot the machine from a live USB and copy the data off. Either way the broken operating system becomes irrelevant.
That is worth doing before attempting any repair. Windows Startup Repair, a system restore or a reinstall all write to the drive, and if the underlying problem is a failing disk rather than damaged boot files, those are hours of writes on hardware that may not survive them.
Where the drive is absent from the BIOS or making noise, none of that applies — the data comes back through imaging on separate hardware. In Manchester that is from £300 +VAT after a free 48-hour diagnostic, and where the drive turns out to be healthy and the machine dead, we price it as the short copy job it is.
That the machine started up correctly, went looking for something to boot from, and found nothing usable. It says nothing about your files — boot files occupy a few hundred megabytes, and everything else on the drive is unaffected.
Unplug every removable device — USB sticks, SD cards, phones, external drives — and restart. The firmware trying to boot from one of those is genuinely the commonest cause, and it takes thirty seconds to rule out.
Enter the BIOS and see whether the drive is listed. If it is, the hardware is communicating and the problem is boot configuration or damaged boot files. If it is absent entirely, that is a connection, controller or drive fault.
Almost certainly not. Booting and reading are separate things — the operating system failing to start has no bearing on whether your documents and photographs are intact. They usually are.
Not before securing your data. Both write to the drive, and if the real problem is a failing disk rather than damaged boot files, that is hours of writes on hardware that may not survive. Copy your files off first.
Yes, and it is usually straightforward. Remove the drive and connect it to another computer with a USB adapter, or boot from a live USB and copy the data off. The broken operating system stops mattering once the drive is being read directly.