External Disk Disconnects Only During Large File Transfers

A drive that disconnects under sustained copying may have a power, cable, enclosure, thermal, or disk problem. Repeating the same transfer does not identify which cause is responsible.

What to check first

Record whether the failure occurs after a similar elapsed time or at the same file. Distinguish an unstable connection from a repeatable unreadable region.

A practical recovery sequence

1. Locate and preserve the evidence. If the disk is stable and makes no abnormal sounds, try one known-good direct connection with the correct power supply.
2. Check the most relevant recovery source. Copy a small set of priority files to healthy storage and watch for new errors. Stop if disconnections continue or the drive becomes abnormal.
3. Keep a separate working copy. Use existing backups or professional recovery for important data rather than running endless transfer retries. Replace suspect hardware only after considering enclosure compatibility and encryption.

Keep the recovery attempt reversible

Device identification comes before repair. Record the model, capacity, and connection so that source and destination cannot be confused. Recovery output must go to separate healthy storage. A device that clicks, repeatedly disconnects, or develops read errors needs a different plan from a healthy disk with an accidental deletion. For valuable data, professional assessment can be preferable to repeated experimentation. Neither a successful mount nor a long list of scan results guarantees that file contents are intact.

How to verify the result

Check destination file sizes and open the copied files; interrupted transfers can leave incomplete outputs with plausible names.

Record which files you checked and which remain uncertain. Keep unverified candidates separate from files you have confirmed are usable; that distinction matters if someone else needs to continue the work.

The mistake to avoid

Do not assume that a file at the destination is complete merely because its name appeared before the disconnect.

If files are still missing

For an actual deletion from a stable, accessible local device, Drecov’s data recovery resources provide another starting point. If you choose to evaluate its software, use the Drecov download, confirm support for your device and filesystem, and keep installation and recovered output off the affected storage. Recovery is not guaranteed. Software cannot substitute for missing encryption credentials, cloud permissions, or unreadable hardware.

Browse related data recovery guides for other storage situations. For platform-specific controls, use the official references below; menu names and available recovery options vary with application, account, and operating-system version.

References and further reading

• CGSecurity: disk imaging and damaged storage
• Apple: what erasing and reformatting a disk does