Decide whether the data is irreplaceable
If the drive holds the only copy of important files, avoid formatting, initialising or repair commands. An unreadable drive needs a data-first plan; being visible in a disk utility does not prove its contents are intact.
Check simple connections cautiously
If there are no unusual sounds or damage, test a compatible cable and direct port, following the drive's power guidance. A successful connection helps investigation but does not guarantee long-term drive health.
Distinguish detection from mounting
A drive may appear in Disk Management without a usable volume or drive letter. File-system compatibility and encryption also matter. Do not accept a format prompt just because Windows cannot read the files.
Stop if failure seems physical
Unusual mechanical sounds, repeated disconnections or worsening access justify stopping repeated power cycles and obtaining advice. Share the model, history and backup status; recovery success and timescale cannot be promised from these symptoms.
Questions about this guide
What should I check before assuming the external drive failed?
Note whether it appears in the operating system's disk tools, try a supported cable or port and record any messages. If the data matters, avoid experiments that format or initialise the drive.
Should I accept a prompt to format the drive?
Do not format a drive containing files you need. A format prompt does not establish that the files are safely backed up or that formatting is the right recovery step.