A WD Passport external hard drive may become corrupted and unreadable due to a number of reasons. These can range from physical damage, to malware infections, to software/firmware issues. In some cases, the issue could be related to the file system or the disk structure itself. It is important to diagnose the specific cause in order to find an appropriate solution for the issue. To do this, users should look for signs of physical damage, run anti-malware scans, and update their drivers/firmware. Additionally, it is important to back up any important data before attempting any recovery methods. By properly diagnosing the issue and taking appropriate steps, users can often get their WD Passport working again.