‘The disk you inserted was not readable by this computer.’ Fix

Have you seen anything like this before? In my case, if I load my Kontakt 4 sampler (as standalone) with external USB hard disk with time machine backup system activated, the disk just shuts down and never comes back again. And if I plug the USB port again, I get the message ‘The disk you inserted was not readable by this computer.’ and the disk is still not operational. I can’t understand the whole situation, but I assume it’s some kind of logical error on the Mac OS file system.

Anyway, since I was using it as a backup drive, I just did a clean format and backup the system from scratch. But after some research, I’ve found out that it can be fixed very easily with a single terminal command.

If you get the message above, click ‘Initialize’, then ‘Disk Utility’ will pop up. Ignore disk utility, and run ‘Terminal’, then type

diskutil list
(check your hard disk ID)  

sudo gpt recover /dev/disk3
(insert your hard disk ID instead of disk3) Type in the password if asked. It’s done. try to plug in your USB port again and check if it works. Of course all of your data should be fine.


‘The disk you inserted was not readable by this computer.’ Fix — 27 Comments

  1. After typing that in Terminal, the response was: “no primary or secondary GPT headers, can’t recover”

    Any suggestions??

    • like I said above, check your disk ID..

      it will look like disk1, disk2,

      replace your disk ID with disk3
      sudo gpt recover /dev/disk3

  2. my disk ID is disk1

    I have the following msg too –

    gpt recover: /dev/disk1: no primary or secondary GPT headers, can’t recover

    • Hi jojo….

      unfortunately.. this method doesn’t work for all circumstances…
      I guess the disk is damaged for good.

  3. I’m confused about the password. In Terminal, I typed in sudo gpt recover/dev/disk2 (my external Lacie drive) and was asked for a password. Is this the password for the external drive? I don’t usually put passwords on my drives. I hit return because I suspect the drive has no password, but Terminal kept asking me for a password.
    This was my backup drive. (I had made many, many back up DVD’s, but to chaotic circumstances, they are lost and the drive died before I had a chance to back up everything.) Initially, the drive wouldn’t start up, which I attributed to the drives power supply connector. I had a tech guy (who claimed he was dual platform) look at it and he replaced the drives housing. Now, the drive does power up but won’t mount. I tried disk utility and got this error message: filesystem verify or repair failed.
    I called to the tech guy and he didn’t have any answers for me. I’m not a tech guy and don’t know the proper tech lexicon to be looking for answers online. So, now I’m at a loss for what to do. Ideas or advice, please.

    • the computer is asking for the user password. the password when you put in to log into your main desktop.
      if you want to change the password, type…
      check System Preferences-> users & groups then check the current user and you’ll see ‘Change Password’ on the right side.

      • Thank you for your reply. If anyone is having the same problem, here is what I did: I didn’t have a password assigned to my laptop. Terminal kept insisting I put a password in so I went to systems prefs and added a password. Doing that got me to the next level. (where it asks for the PW hint, I typed in the PW in case I forget it.) I then typed in “sudo gpt recover/dev/disk3″ in Terminal (disk3 is the correct disk for me) but now I get a message “gpt: unknown command: recover/dev/disk3″. I used a program called Disk Drill to scan the drive. It took nearly 72 hours to scan my external Lacie T1 drive. What I didn’t know when I downloaded the “free” software was that I need to upgrade to the Pro version ($75) to recover the data, which I’ll do. In the meantime, I’m running DiskWarrior, which has been stuck in Step 1 (searching entire dsk in final rescue attempt) for several hours. I researched this online and several folks have had this issue, some saying it took nearly a month for DW to repair the drive.
        Question: Why is Terminal telling me the command is unknown? (oh, the drive the formatted for Mac, no partitions but DU says Partition Map Scheme :Apple Partition Map, SMART status not supported.)
        Lastly, I’ve read a lot of things saying “back up, back up, back up your drives.” Here’s the thing: I did back up this drive. I had about 75 cds and DVDs of back ups. We moved and I put the back up disks in a box which never made it to our new flat. I didn’t know this until two weeks later when my drive died. So, back up, but put your back ups either in a safe deposit box or on a cloud. Thanks for reading. Any advice or comments sincerely appreciated.

  4. It doesn’t seem to be working….

    I type in sudo gpt recover /dev/disk0
    But it says:
    gpt recover: unable to open device ‘/dev/disk0′: No such file or directory

    Are the spaces correct and am i choosing the right number?
    The one at the top that says /dev/disk0 or the identifier that says disk0s2?

    • the disk0 should be fine..(no 0s2 or s3) I just want to see your computer myself… hum… did you check by typing diskutil list?

      • Yes i did and it had a top one that said /dev/disk0 and another was /dev/disk1 i think for the usb that isn’t working…

        will try again and see what happens

        • It asked for the password this time but it said
          gpt recover: unable to open device ‘/dev/disk0′: No such file or directory
          Do i insert the USB stick before or after typing in the password?

          • It’s really difficult to understand the situation by only seeing the text. but this method doesn’t cover all cases for logical errors. maybe your disk is already dead. try clean formatting it, if you just want to use the disk.

  5. Hi! I’m receiving the same message. However, after going through all the steps and proceeding with the password, it says “gpt: unknown command: recover/dev/disk1″ What do I do now?


  6. Hi, I got the same error message and I am down to the password part of the Terminal. Then it says something like “make sure you type sudo correctly….or you could loose important files or data”. I am certain that I followed the directions and my ID is correct but I am still a little hesitant to put the password in and enter because of the warning. What’s the worst I could do if say I didn’t do the spacing correctly or something? Thanks in advance for any response! Cheers!

  7. I got the same message as steve there, and I too am very hesitant.. I can’t afford to lose these files. What are the chances that it will work? And if the command doesnt work, what are the chances that it’ll just leave it be and not do an entire restore? Thank so much, you’re definitely a big help. A little panicky here.

    • first. try to connect it in a different mac or any computer. then do the same thing as above. see what it has to say. the command only works on mac os journeled GPT formatted disks BTW.

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