uk Technology & digital loss

What to do if…
your computer will not boot or cannot detect its startup disk and you still need the files

Produced and maintained by PanicStation.org Published: 24 July 2026 Last reviewed: 16 August 2026 Editorial policy UK guide

Short answer

Do not erase, initialise, format, reset or reinstall anything while the computer holds the only copy of the files. Record what is happening, check for existing copies elsewhere, and make preserving the files the priority before attempting repairs.

Do not do these things

Do not accept an option that says it will erase, initialise, format, repartition, reset or remove everything.
Do not repeatedly power on a disk that is clicking, grinding, scraping or repeatedly spinning up and stopping.
Do not open a sealed hard drive or try freezing, heating, striking or dismantling it.
Do not install recovery software onto the affected startup disk.
Do not save recovered files back onto the affected disk.
Do not run unfamiliar repair commands or change firmware settings at random.
Do not hand over passwords or encryption recovery keys until you have checked who will receive them and why they are needed.
Do not let a repair service replace or wipe the disk without your clear permission.

What to do now

Photograph the screen and write down the exact message, error code, sounds and lights. Note whether the problem followed an update, power cut, drop, liquid spill or other incident.
If there is smoke, a burning smell, unusual heat or liquid damage, switch the computer off and disconnect it from power if this is safe. Do not turn it on again before obtaining appropriate technical advice.
If a hard disk is making persistent clicking, grinding or scraping sounds, stop using it. Continued use may worsen physical damage, so contact a specialist data-recovery service when the files are important and not backed up.
From another device, check whether the files already exist in cloud storage, email attachments, shared folders, an external backup, another computer, a phone or an organisation’s system. Keep any existing backup separate from the affected computer.
With the computer switched off, disconnect non-essential USB devices, memory cards, hubs, docks and external drives. Reconnect its normal power supply and try starting it once.
If the missing startup disk is external and is not making unusual sounds, try one known-good compatible cable and another suitable port. Stop if the disk repeatedly disconnects or begins making abnormal noises.
Preserve anything that may unlock an encrypted disk, including the computer login, Microsoft account details, BitLocker recovery key, Apple Account details or FileVault recovery key. Contact the organisation’s IT team first if the computer belongs to an employer, school or university.
If the computer or disk becomes readable and appears stable, copy the irreplaceable files first to a separate healthy storage device. Copy rather than move them, and check that several copied files open correctly.
If the disk remains inaccessible, tell any technician in writing that recovering the files is more important than restoring startup. Ask them not to reset, erase, reinstall, repair, replace or write to the disk without your permission, and ask whether they can copy or image it before repair attempts.
Consider Windows Startup Repair, macOS Disk Utility First Aid, system reinstallation or other repair tools only after the files are backed up or a competent technician has assessed the risk to the data.

What can wait

You do not need to decide now whether to replace the computer, buy recovery software, reinstall the operating system, replace the disk or reorganise your backups. Those decisions can wait until the important files are safely copied or the disk has been assessed.

Important reassurance

A computer failing to boot does not by itself mean the files have been erased. The cause may involve startup software, a connection, encryption or the storage device, but protecting the original disk now gives you the best chance of avoiding preventable loss.

Scope note

This guide covers immediate steps to protect files when a computer cannot start or detect its startup disk. Diagnosis, physical repair, disk imaging and data recovery may require specialist help.

Important note

This is general information, not professional data-recovery, cybersecurity or hardware-repair advice. Seek appropriate technical support when the files are irreplaceable, the disk may be physically damaged, or the computer contains confidential work, client or organisational data.

Additional Resources

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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