DriveDx vs MHDD

DriveDx monitors and diagnoses SSD and HDD health on macOS, with the aim of helping users identify drive trouble before data loss or downtime. It evaluates indicators such as SSD wear and write endurance, I/O errors, pending sectors, and reallocated bad sectors. Its reports distinguish Warning, Failing (Pre-fail), and Failed states. The app can run in the background, check drives periodically, and alert users when it detects an issue. Users can initiate and control self-tests of electrical or mechanical performance and read performance. DriveDx calculates health and performance ratings, plus an indicator of remaining SSD lifetime. It can email problem alerts and drive status reports, with reporting configurable by criteria, and can alert users when free space crosses a chosen threshold. The product page lists compatibility from macOS 10.9 through macOS 26 and invites users to try it free, without specifying a trial length. There is no free plan. The personal license costs $19.99 as a one-time purchase for up to three personal computers and non-commercial use; other licenses cover household or commercial computer counts.

MHDD is a freeware utility for low-level hard drive diagnostics and management. It supports IDE, Serial ATA and SCSI drives, and can access USB storage through USB-to-SCSI emulation drivers. Diagnostic tools scan drives, show SMART attributes, run tests and log scan results. Drive operations include low-level erasing, sector reads and writes, bad-sector remapping, and changing drive size with HPA. A simple scripting engine and batch-file support allow tests to run without an operator. The maker offers the software as a CD image, self-extracting floppy image or archive of executable files. The manual lists an Intel Pentium or higher, 4 megabytes of RAM, a keyboard, and DR-DOS or MS-DOS 6.22 or higher as requirements. It notes that some AHCI controllers may not be recognized, with IDE or Legacy mode suggested if needed. The manual warns that MHDD can damage a drive or cause data loss, particularly around erase or remap operations, and advises backing up first. It also says the tool is difficult for people without deep knowledge of disk drives. MHDD is listed at free.