While specific diagnostic codes can vary by manufacturer, typically indicates a physical hardware failure or a high number of bad sectors that the drive can no longer manage . This error usually appears during pre-boot hardware tests, such as those on Dell or HP systems, signaling that the drive is unstable and may fail completely at any time. What Return Code 4 Means
Return Code 4 is a "critical failure" signal. It often indicates that the drive's built-in (Self-Monitoring, Analysis, and Reporting Technology) system has detected internal parameters—like read/write retry counts or reallocated sectors—that have exceeded safe operational limits. Hard disk error (3F4) - HP Support Community - 8066854 Hard Drive Diagnostics Return Code 4