How to Check Drive Health on Mac (SMART Status)

Drives rarely die without warning — they log their own health, and macOS will show it to you if you know where to look. A thirty-second SMART check tells you whether your disk is fine or whether you should be backing up right now.

Check SMART status in Disk Utility

1. Open Disk Utility (in Applications → Utilities).
2. Choose View → Show All Devices so physical drives appear, not just volumes.
3. In the sidebar, select the top-level device — the hardware name like APPLE SSD AP0512Z — not the indented Macintosh HD volume beneath it.
4. Read the S.M.A.R.T. status field in the drive details.

You'll see one of three values. Verified means the drive's self-monitoring reports no problems. Failing means the drive has detected hardware degradation and is predicting its own death — treat it as an emergency. Not Supported is common on external USB drives: most USB enclosures don't pass SMART data through, so macOS simply can't see it. That's a limitation of the enclosure, not a verdict on the drive.

This works the same on macOS 13 Ventura, 14 Sonoma, and 15 Sequoia.

Deeper checks in Terminal

The built-in tools can tell you more than the one-word verdict:

# quick SMART verdict for the internal drive (read-only)
diskutil info disk0 | grep SMART
# full details on Apple silicon / NVMe Macs
system_profiler SPNVMeDataType
# SATA drives and many externals
system_profiler SPSerialATADataType

For the full table of SMART attributes — wear level, spare capacity, error counts — install smartctl from the open-source smartmontools package (requires Homebrew):

# install, inspect, and (if you like) remove afterwards
brew install smartmontools
sudo smartctl -a /dev/disk0
brew uninstall smartmontools

All of these commands only read information — they change nothing on the drive. If disk0 isn't the drive you're curious about, run diskutil list first to see every attached disk and its identifier, then substitute the right one. External drives usually show up as disk2 or higher.

How to read the results

• Verified means passing today. SMART is good at catching gradual wear (bad sectors, flash exhaustion) but can't predict sudden controller or power failures — so a green status never replaces backups.
• On an SSD, the numbers to watch in smartctl output are Percentage Used (of rated write endurance — near 100% means the flash is worn) and Available Spare (replacement cells left — falling toward its threshold is a bad sign).
• On a hard disk, rising Reallocated_Sector_Ct or Current_Pending_Sector counts mean the platters are shedding sectors. A drive that's also clicking or grinding is on borrowed time regardless of what SMART says.

If the status says Failing

Back up immediately — start Time Machine now, and copy your truly irreplaceable files (photos, documents, keys) to another disk or cloud storage first, in case the drive dies mid-backup. Don't run repair utilities repeatedly on a failing mechanical drive; the extra thrashing accelerates the decline. Then replace the drive: for an external, the fault may be the enclosure rather than the disk inside, so testing the bare drive in another enclosure is worth a try. For a Mac with soldered internal storage — every Apple silicon Mac — a failing internal SSD means a trip to Apple or an authorized service provider.

Healthy drive, flaky volume?

SMART reports on the hardware; it says nothing about the file system on top of it. If the drive passes but you're seeing odd behavior — files that won't copy, volumes that unmount — run a structure check next: see our guide to running First Aid in Disk Utility.