I am wondering if there is a utility for the mac that allows you to see the details of an SSD like the health of the drive, TBW (total bites written), how many running hours etc... In researching for an app of such a kind I found (SSDLife) for windows? It looks like to me that a program like this would be exactly what I would need. The most important information that I need to know about is the TBW (total bites written) on the drive. Because I have heard that once an SSD drive reaches a certain amount of writes it becomes a read only drive, so this information would be invaluable to me.

  • I could really use some help on this one!
    – Stephen
    Commented Nov 4, 2012 at 23:25

5 Answers 5


Check out SSD Health on the Mac App Store: http://ssdhealth.com/macos.html

  • Is it possible to get a trial version?
    – Stephen
    Commented Nov 5, 2012 at 17:14
  • I don't think so. You could try emailing them: [email protected]
    – swr
    Commented Nov 5, 2012 at 22:52

If you're OK with Command Line utilities, you can always use smartmontools from http://www.smartmontools.org/.

You would need XCode to compile them from source (unless someone here knows binary distribution for Mac OSX), but if I remember correctly I had no issues compiling the package.

I have an OCZ SSD retrofitted into my MBP 15" mid-2010 and I can use smartctl command to monitor various stats, including your Total Bytes Written (called here Lifetime_Writes) as well as Media Wearout Indicator (shown as percentage).

To give you an idea, here's the example output:

MacBook:~😈  smartctl -a /dev/disk0 
smartctl 6.0 2012-10-10 r3643 [x86_64-apple-darwin12.2.0] (local build)
Copyright (C) 2002-12, Bruce Allen, Christian Franke, www.smartmontools.org

Model Family:     Indilinx Everest/Martini based SSDs
Device Model:     OCZ-VERTEX4
Serial Number:    OCZ-xxxxxxxxxxxxxxxxx
LU WWN Device Id: 5 e83a97 49c31f44c
Firmware Version: 1.5
User Capacity:    512,110,190,592 bytes [512 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Sat Apr 20 23:39:33 2013 IST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00) Offline data collection activity
                    was never started.
                    Auto Offline Data Collection: Disabled.
Self-test execution status:      ( 249) Self-test routine in progress...
                    90% of test remaining.
Total time to complete Offline 
data collection:        (    0) seconds.
Offline data collection
capabilities:            (0x1d) SMART execute Offline immediate.
                    No Auto Offline data collection support.
                    Abort Offline collection upon new
                    Offline surface scan supported.
                    Self-test supported.
                    No Conveyance Self-test supported.
                    No Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                    power-saving mode.
                    Supports SMART auto save timer.
Error logging capability:        (0x00) Error logging NOT supported.
                    General Purpose Logging supported.
Short self-test routine 
recommended polling time:    (   0) minutes.
Extended self-test routine
recommended polling time:    (   0) minutes.

SMART Attributes Data Structure revision number: 18
Vendor Specific SMART Attributes with Thresholds:
  1 Raw_Read_Error_Rate     0x0000   006   000   000    Old_age   Offline      -       6
  3 Spin_Up_Time            0x0000   100   100   000    Old_age   Offline      -       0
  4 Start_Stop_Count        0x0000   100   100   000    Old_age   Offline      -       0
  5 Reallocated_Sector_Ct   0x0000   100   100   000    Old_age   Offline      -       0
  9 Power_On_Hours          0x0000   100   100   000    Old_age   Offline      -       2981
 12 Power_Cycle_Count       0x0000   100   100   000    Old_age   Offline      -       417
232 Lifetime_Writes         0x0000   100   100   000    Old_age   Offline      -       14566414269
233 Media_Wearout_Indicator 0x0000   100   000   000    Old_age   Offline      -       100

SMART Error Log not supported

Warning! SMART Self-Test Log Structure error: invalid SMART checksum.
SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]

Selective Self-tests/Logging not supported

The exact parameters and stats shown for your SSD might vary, but as it's a free tool, you can try and see for yourself!

  • 4
    There is a port in macports port install smartmontools and for most people will be a binary download - you still need Xcode command line tools for macports
    – mmmmmm
    Commented Apr 21, 2013 at 23:52
  • Oh, cool. I was wondering about that, but since I don't use macports, fink or any other package tools / systems, I wasn't sure.
    – mike
    Commented Apr 22, 2013 at 23:53
  • 14
    You can also install this with brew: brew install smartmontools Commented Feb 16, 2015 at 9:59
  • Hmm my SSD has no Media_Wearout_Indicator, default SSD in rMBP (smartctl reported model: APPLE SSD SM0512F)
    – xref
    Commented Feb 16, 2015 at 23:54

Check out DriveDx: http://binaryfruit.com/drivedx . It have free 10-Day Trial version and shows Lifetime Left indicator for SSDs, overall health rating, performance rating, important health indicators and many other useful and important information about SSD.


DriveDX Screenshot of my MacBook Pro Retina August 2012

I have owned a MacBook Pro Retina since August 2012 and it gets modest use, with mainly web browsing and online video streaming as the main uses. As the DriveDX report shows, the SSD is rated at 90% after 3.5 years of use.

My MACs seem to last forever, with an iMac 27" from 2009 still running fine - though I maxed out the memory and replaced the regular hard drive with an SSD this year... Still cranking along after 6 years, so I can see why people may be worried about wearout, but like most things with Macs.. you seem to pay them big money up front and once you have paid the premium, their hardware choices really seem to provide long life for the average mac user...


This isn't a software recommendation (I see there are already a few posted), but more of a tip. Although SSDs do have a shorter "life" than HDDs, it is still by far a longer life than you'd reach with normal conditions. Your SSD will outlast its own desirability and that of the computer it's in, i.e. by the time it craps out, you probably would have wanted to upgrade your computer anyway. Moral of the story: don't worry about it.

From OCZ's FAQ

"...Generally, you should get many years of solid use out of your SSD…"

  • I have had my Macbook Air for just over a year and got a warning about my drive. Using the above tools, I found that my "Wear Leveling Count" is critical. Not sure why, but it does happen.
    – brianestey
    Commented Apr 7, 2015 at 15:36
  • Strange, is there any visible consequence of that? Though i don't understand the paranoia and need to constantly be worrying about your computer and micro managing it's most mundane aspects, it's unhealthy and usually futile.
    – Alexander
    Commented Apr 7, 2015 at 15:47
  • Yes, there is a consequence. My SSD is on the verge of dying and I have an appointment tomorrow with the Genius bar at my local Apple store to see if it is as critical as the message implies. I normally don't worry about such things but when the OS tells me to, I do.
    – brianestey
    Commented Apr 8, 2015 at 2:29
  • Your description isn't very clear, you say it's on "verge of dying", but don't even know if it's "as critical as the message implies." I presume you got a warning from the OS, what did it say exactly?
    – Alexander
    Commented Apr 13, 2015 at 23:23
  • Windows in bootcamp said "Windows detected a hard disk problem" which kicked off some scrambling to find out what was wrong. "Disk Utility" in the Mac side says "This drive has a hardware problem that can't be repaired." with the bottom "S.M.A.R.T. Status" just saying "Failing". Not satisfied with this, I downloaded DriveDX and found that the Wear Leveling Count was critically past the threshold. This Macbook Air was just about a year old.
    – brianestey
    Commented Apr 15, 2015 at 0:07

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