How to Check SSD Health on Mac: From Disk Utility to Terminal Wear Metrics

Method 1: The Quick Built-In Check (Disk Utility)

Disk Utility can display S.M.A.R.T. status when the selected storage device exposes that information to macOS. The information available depends on the device and storage interface.

Steps to check S.M.A.R.T. status:

1. Open Disk Utility (press Command + Space, type Disk Utility, and press Return).
2. Click the View menu in the top-left toolbar and select Show All Devices (or press Command + 2).
3. In the sidebar, select the top-level physical drive (e.g., APPLE SSD AP0512R or Apple Fabric Type 1), rather than the indented APFS container or volumes underneath it.
4. Look at the information panel at the bottom of the window, or click the Info (ⓘ) button in the toolbar (the exact placement can vary across macOS versions).
5. Locate the S.M.A.R.T. status field: Verified indicates that the device's reported S.M.A.R.T. status does not currently indicate a failure condition. It does not guarantee that every health metric is normal or that the drive cannot fail. Failing indicates that the device reports a failure condition. Back up important data immediately and investigate the storage device.

Read more: Apple Support: Disk Utility disk information and available space

Why "Verified" Isn't the Whole Story on Modern Macs

Some older Macs allowed internal storage replacement, although the storage design varied by model. Most modern Apple silicon Macs use internal onboard storage as part of Apple's integrated storage architecture. The storage design and serviceability vary by model.

Apple silicon Macs use a hardware-rooted secure boot process involving Boot ROM, LLB, iBoot and LocalPolicy. The LocalPolicy is signed by the Secure Enclave Processor and stored on the internal drive. Even when starting macOS from an external drive, the Mac requires an internal LocalPolicy configuration. Because Apple silicon boot and recovery depend on internal system components and boot-policy data, a severe internal storage failure can prevent normal startup or recovery. The outcome depends on which components are affected.

Verified is a general health indication, not a detailed endurance measurement. A drive may report significant estimated endurance consumption while still reporting no critical S.M.A.R.T. failure condition. Inspect the available health metrics separately where supported.

Read more: Apple Platform Security: Boot process for a Mac with Apple silicon · Apple Platform Security: Startup Disk security policy control

Method 2: The Detailed Method (Terminal & smartctl)

smartctl can retrieve available S.M.A.R.T./NVMe health information on supported Mac storage devices. The attributes exposed depend on the storage hardware and macOS interface.

Step 1: Install smartmontools

If you use the Homebrew package manager, open Terminal (Applications > Utilities > Terminal) and run:

(If you do not have Homebrew, you can install it in seconds from brew.sh, or use a standalone GUI monitoring tool like DriveDx.)

Step 2: Query your internal SSD

Identify your primary drive identifier (typically disk0 for the internal NVMe storage) and run smartctl with administrator privileges:

Type your Mac administrator password when prompted (Terminal will not display characters while typing) and press Return.

Step 3: Read the NVMe Health Log

Scroll down until you locate the section labeled SMART/Health Information (NVMe Log 0x02). The following is an illustrative example of NVMe S.M.A.R.T. output. Actual attributes and values vary by SSD model, controller, firmware and operating system:

Error Information Log Entries counts error-log entries recorded over the controller's lifetime. It is separate from the Media and Data Integrity Errors counter and should be interpreted with the corresponding error information.

Read more: smartmontools: smartctl manual (Darwin / macOS device support)

How to Decode Your SSD's Health Metrics

The NVMe specification standardizes health reporting for NVMe-compatible storage devices through its SMART/Health Information log. Here is how to evaluate the reported attributes:

Understanding "Percentage Used"

Under the NVMe specification, Percentage Used is a vendor-specific estimate of consumed NVM subsystem endurance. A value of 100% means the estimated endurance has been consumed, but does not necessarily indicate device failure. Values above 100% are permitted. Monitor Percentage Used periodically to understand estimated endurance consumption, and maintain regular backups regardless of the reported percentage.

Read more: NVM Express Base Specification: SMART / Health Information Log (Log Page 02h)

What Influences Mac SSD Write Activity and Degradation?

SSD endurance is primarily affected by writes and NAND program/erase (P/E) cycles. Normal read operations contribute negligible wear, although repeated read activity can introduce read-disturb effects in NAND flash. Several workload and storage-management factors can influence SSD write activity and endurance: 1. Virtual Memory Swap Activity: When memory pressure increases, macOS can compress inactive memory and use storage on the startup disk for swap files. On memory-constrained Macs running sustained memory-intensive workloads, macOS may use more swap storage. Repeated swap activity can contribute to additional SSD host writes. 2. Storage Capacity and Write Amplification: NAND flash is programmed in pages and erased in larger blocks containing multiple pages. Their sizes vary by NAND technology and SSD implementation. SSDs use out-of-place writes: when available clean blocks become scarce, the controller may need to perform garbage collection, moving valid pages and erasing blocks to create room for new writes. Operating an SSD with very little available space can reduce the controller's flexibility for garbage collection and may increase write amplification, particularly under write-intensive random workloads. The actual effect depends on the SSD's over-provisioning, TRIM support, and workload. 3. Cache and Temporary File Turnover: Downloading, updating, importing, or converting local AI models can generate substantial writes. Once loaded, model weights are generally read for inference, while additional cache and log writes depend on the application and workload. Xcode builds, video scratch disks, and package-manager operations can also generate writes over time.

Practical Checklist: Storage Practices for Mac SSDs

You do not need to obsess over every write cycle, but four practical habits help you manage storage capacity and monitor drive health effectively:

• Maintain sufficient free storage capacity: Diskfern recommends maintaining 15% to 20% free storage as a practical housekeeping target. This helps provide sufficient headroom for macOS updates, temporary files, and controller garbage collection under write-heavy workloads. This is not an official Apple or NVMe requirement and does not guarantee longer SSD lifespan.
• Monitor memory pressure in Activity Monitor: Open Activity Monitor > Memory. Consistently yellow or red memory pressure, particularly alongside sustained swap activity, may indicate that your Mac is under memory pressure. Remember that Swap Used is the current amount of disk space allocated to swap, not a cumulative SSD-write counter. A large Swap Used value alone does not establish how much data has been written to the SSD.
• Offload static, massive media libraries: Move completed video exports, raw archives, and static sample libraries to an external USB or Thunderbolt drive rather than leaving your internal drive at near-full capacity.
• Periodically review large files and dormant data: Use built-in tools or a dedicated storage utility. Diskfern (diskfern.com), for example, is a native macOS storage analyzer that maps disk usage visually, flags heavy developer artifacts like Xcode simulators and build caches, and helps you identify disposable files so you can reclaim storage capacity.