When a drive starts clicking, disappears from the computer or shows an error, the safest first move is usually to stop using it. Repeated attempts can turn a recoverable issue into a more serious one.
Do not format the drive, run repair utilities repeatedly or open it in an ordinary environment. If the files are valuable, keep the device powered down and note what happened immediately before the failure.
A recovery assessment should establish the type of failure, the health of the device and the safest path to make a copy. The original should be treated as evidence, not as a working disk.
After recovery, build a prevention plan with at least one separate backup and a way to test that the backup can actually be restored.