So, I've found myself in a quite tight spot regarding my internal HDD.

I've got a 13" Late 2011 MBP, running macOS 10.12.1, which is behaving very strangely lately: Mail will refuse to open, with an error message complaining about network and home folder problems; Finder won't let me create new directories (they appear and then instantly vanish - they weren't created at all, according to my Dropbox log); and Disk Utility gives inconsistent results: sometimes it will say everything's fine, while other times it indicates disk corruption.

Stranger still, is that no external storage appears on my Desktop. They do show in System Information under the respective USB controller, but no signs of life either from Finder or Disk Utility.

I've tried rebooting the system to see if things would come back to normal; instead, I was greeted to a Kernel Panic at startup, complete with white text under a black background. After trying to use the recovery partition to run Disk Utility again, a second attempt would result in a "block sign" being displayed if I tried accessing said partition, and Internet Recovery's Disk Utility just hang up after an hour checking the Catalog File.

I was only able to boot back into macOS by trying to boot into verbose mode (Cmd+Shift+V), and for some reason the system came back to life. It still has the exact same problems as before, with the addition that, after choosing to send Apple a Crash Report, the "ReportCrash" process is now taking an entire processing core for about an hour, with no signs of high disk activity.

This is quite frustrating, given that it's been about 6 months I've replaced its original 750GB HDD for a 1TB Toshiba hybrid drive (1TB disk; 8GB flash), and things were working very smoothly until then.

Before I reboot my Mac again, I'd like to know if anyone has ever encountered a similar isse, and what can be done to minimize the damage. I have a 30-day-old Time Machine backup, and can read the drive using a secondary Linux machine in order to not lose more data, but as-is, what is the best course of action?

EDIT: After following @Allan's suggestion and running the Apple Hardware Test (online version) on extended mode, the HDD is indeed reported. The output is as follows:

Test Results

Alert! Apple Hardware Test has detected an error.

4HDD/11/40000004: SATA(0,0)

Pass Number: 1,
Total Time Testing: 44 mins 53 secs

Guess I'll try to image the HDD this night under Linux, using ddrescue, and restore to the older 750GB HDD; I'll follow up with more progress later. Thanks to @jksoegaard and @Allan for the moment!

EDIT 2: On trying ddrescue the drive oddly reported no read errors, even though almost every time I run it through fsck.hfsplus the reported results are different. I've also decided to check its S.M.A.R.T. data; to my surprise, it reports no reallocated sectors, but an alarmingly high rate of UDMA CRC Errors (11752, out of a 253 worst-recommended value).

I've decided to try to save as most as I could from my home directory using the Linux machine (fortunately only a couple uninportant files seemed corrupt, even though macOS refused to read the disk through an external SATA<->USB converter), and put back the original 750GB HDD on the MacBook, which is being currently restored from the aforementioned Time Machine Backup.

Next step is to return the HDD under warranty and try to claim a new one, I suppose. Thanks so much to everybody for the help!

  • 1
    Have you tried running Apple Hardware Test (AHT)? Hold the D key while booting from a powered off state with the AC adapter connected. I find it unlikely, not not impossible that a 6 month old drive has failed.
    – Allan
    Commented Nov 12, 2016 at 12:08
  • I agree with @Allan that it's unlikely although not impossible that your Hybrid drive is failing. In addition to trying to run Apple Diagnostics, what happens if you start in Safe Mode (i.e. Startup while pressing the Shift key down)? By the way, if you can't get Apple Diagnostics to run, you can also try holding down both the Option and D keys at startup to run Diagnostics from the internet.
    – Monomeeth
    Commented Nov 12, 2016 at 12:17
  • It is actually not unlikely. Drives mainly fail either early or late. Look at statistics from for example Backblaze or Google. Either drives die within the first year, or they generally survive 4-5 years before they start failing in numbers again.
    – jksoegaard
    Commented Nov 12, 2016 at 12:44

2 Answers 2


The best course of action is to use the secondary Linux machine to read the drive and make a bit-for-bit copy as soon as possible. Use a program such as ddrescue to ensure you get as possible out.

After you've made the copy, do any recovery attempts of file contents on the image you've created with ddrescue.

Your hybrid drive is most probably failing and failing fast. Hybrid drives have a lot more failure modes than a regular hard drive or SSD drive, so that's why you can experience very odd things happening - without for example it being the same sectors that are "bad" all the time.

You'll need to replace the drive. As it is only 6 months, perhaps you can get it replaced under warranty from the drive manufacturer or seller.


Firstly, back up your data.

Once you have done that, there are some steps you could try to check the health of your drive:

  1. Check SMART status

    This will give you several indications of the health status of your drive. Note that it has been shown that SMART numbers don't always predict drive failure.

    You used to be able to do this in Disk Utility by Apple has dumbed down that piece of software to the point of uselessness. You can do this however, with a 3rd party app such as the free trial of DriveDx, available on the App Store. I have used this several times to check the health of a drive, just be sure to delete it when you're done so it doesn't keep nagging you.

    If when you run the test you have several warnings or pre-failure warnings, it is good bet that your drive is on the way out. Note that not all drives support this.

  2. Disk first aid in Disk Utility

    The Disk Dtility app can attempt to find and fix errors automatically. Open the Disk Utility app, click on the offending physical drive and click "first aid". It will freeze up your system for a few minutes while it works. Repeat this process on all partitions you have on the drive too. It will warn you if it found issues and what it was able to do about them

  3. Repair Permissions.

    I have found this to fix a multitude of issues for me.

    First, open up terminal by pressing CMD+SPACE and enter TERMINAL. Press ENTER.

Then, to see if this might be an issue for you run:

sudo /usr/libexec/repair_packages --verify --standard-pkgs /

And see if there are any files with damaged permissions. You may see something like below. If you have 100s of faulty permissions, it could be another sign of an early disk failure. As always, keep backups.

Permissions differ on "Library/Java", should be drwxr-xr-x , they are drwxrwxr-x .
User differs on "private/var/db/displaypolicyd", should be 0, user is 244.
Group differs on "private/var/db/displaypolicyd", should be 0, group is 244.

So in this example it is a good chance Java permissions are the culprit. To fix them run:

sudo /usr/libexec/repair_packages --repair --standard-pkgs --volume /

And lastly, don't forget to back up!

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