An External HDD Disconnects Before File Copy Finishes: Should You Scan It?
A drive that repeatedly disconnects during file copies should be treated as potentially failing, not as an ordinary deleted-file case. Stop full scans and repeated transfers until you decide how much risk the missing data justifies.
In this r/datarecovery disconnecting-HDD case, the owner had already tried a different cable and port, could not afford a lab, and said most lost items were replaceable. They asked whether a docking station or another scan would help.
Do Not Interpret a Scan That Runs Longer as Proof of Health
The drive staying online for a few minutes does not remove the risk of later read failure. Continued full scans, filesystem repair, and repeated reconnections can consume the limited time a marginal disk stays readable. A docking station may change the interface, but it cannot be assumed to fix an internal drive fault.
Choose Professional Rescue or One Carefully Planned DIY Attempt
If the irreplaceable subset merits recovery expense, stop now and ask a specialist for a diagnosis. If the user accepts the possibility of permanent loss, an experienced operator may attempt error-tolerant imaging to healthy storage, recording a mapfile as GNU ddrescue describes.
Only after a usable copy exists should file discovery and selective export proceed against that copy. If the source is no longer visible as a real block device or deterioration accelerates, do not keep trying software.