iMac Partition Testing: Identify and Fix Disk Issues

Disk Utility First Aid on macOS

Overview

Quick checks to verify partition health on an iMac: run First Aid on each container/volume, check SMART status, and verify mount points. If errors persist, back up immediately and plan a repair or replacement.

Steps

  1. Open Disk Utility and choose View → Show All Devices.
  2. Select the physical drive → run First Aid on the whole device.
  3. Run First Aid on containers and volumes in descending order.
  4. Check SMART status and system logs for disk I/O errors.
  5. If errors repeat, clone data and replace the drive.
  6. After hardware repair, restore from Time Machine or clone.
  7. Rebuild APFS container if corruption remains.
  8. Test with Apple Diagnostics to exclude other faults.
  9. Re-check partitions after several reboots.