External HDD No Longer Accessible (ExFAT formatted)

external-diskhard drivepartition

I have an external HDD Toshiba MQ01ABD100 1TB HDD in an external enclosure. Recently it suddenly no longer accessible. When plugged to a Mac, it will prompt "The disk you inserted was not readable by this computer" with 3 option: Intialize…, Ignore & Eject. I would like to recover the data on this external HDD as I've copied some work files there as backup before I redo my Macbook. I'm using the iMac at work to post this & would be doing the recovery work here too.

Here are the results of some of the commands I saw ran in other topics…

diskutil list

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            999.3 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk1
   1:               Windows_NTFS                         1.0 TB     disk1s1

diskutil info disk1

Device Identifier:        disk1
   Device Node:              /dev/disk1
   Whole:                    Yes
   Part of Whole:            disk1
   Device / Media Name:      MQ01ABD100

   Volume Name:              Not applicable (no file system)
   Mounted:                  Not applicable (no file system)
   File System:              None

   Content (IOContent):      FDisk_partition_scheme
   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 USB
   SMART Status:             Not Supported

   Disk Size:                1.0 TB (1000204886016 Bytes) (exactly 1953525168 512-Byte-Units)
   Device Block Size:        512 Bytes

   Read-Only Media:          No
   Read-Only Volume:         Not applicable (no file system)

   Device Location:          External
   Removable Media:          Fixed

   Virtual:                  No

sudo fdisk /dev/disk1

Disk: /dev/disk1    geometry: 121601/255/63 [1953525168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: 07 1023 254  63 - 1023 254  63 [         2 - 1953525166] HPFS/QNX/AUX
 2: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused

Added: 21/APR/2019

sudo gdisk /dev/disk1

GPT fdisk (gdisk) version 1.0.4

Partition table scan:
  MBR: MBR only
  BSD: not present
  APM: not present
  GPT: not present


***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by
typing 'q' if you don't want to convert your MBR partitions
to GPT format!
***************************************************************

Warning! Main partition table overlaps the first partition by 32 blocks!
You will need to delete this partition or resize it in another utility.

Warning! Secondary partition table overlaps the last partition by
33 blocks!
You will need to delete this partition or resize it in another utility.

ADDED: 23/APR/2019

RESULT of sudo dd if=/dev/disk1 skip=1 count=2 2>/dev/null | hexdump -Cv

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000020  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000040  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000080  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000090  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000100  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000110  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000120  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000130  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000140  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000150  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000160  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000170  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000180  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000190  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000200  eb 76 90 45 58 46 41 54  20 20 20 00 00 00 00 00  |.v.EXFAT   .....|
00000210  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000220  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000230  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000240  02 00 00 00 00 00 00 00  ae 6d 70 74 00 00 00 00  |.........mpt....|
00000250  00 08 00 00 00 f0 00 00  00 f8 00 00 75 6f 74 00  |............uot.|
00000260  0b 00 00 00 bf 56 15 58  00 01 04 00 09 08 01 80  |.....V.X........|
00000270  34 00 00 00 00 00 00 00  f4 f4 f4 f4 f4 f4 f4 f4  |4...............|
00000280  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000290  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002a0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002b0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002c0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002d0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002e0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000002f0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000300  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000310  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000320  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000330  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000340  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000350  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000360  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000370  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000380  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
00000390  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003a0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003b0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003c0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003d0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003e0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 f4 f4  |................|
000003f0  f4 f4 f4 f4 f4 f4 f4 f4  f4 f4 f4 f4 f4 f4 55 aa  |..............U.|
00000400

I've tried reading other posts that came up googling using the error messages and it seems to point to corruption of the partition table ? Hope someone could advice & guide me through this process. It's super frustrating as I can't seemed to be able to fid anything that's similar to this.

Regards,
chris

Best Answer

Before doing any more scans and operations on the device, it is worth connecting the drive to a different device. Mac/Windows just see if it works. It could be that the physical drive may be damaged or shocks could've damaged or corrupted the controller/data.

The fact that it is only recently that it has suddenly changed state would indicate that there may be a problem with the hardware. It is possible, so get it checked just to be sure.

Is the cable you are using USB Micro-B? Check to make sure it isn't bent or damaged. It is unlikely that it would cause this type of fault, but just check to make sure.

I would suggest doing these checks before changing the partition scheme, as that can cause loss of data by erasing and corruption.

Related Solutions

MacOS – Shared data partition for Bootcamp no longer accessible

After a lot of trial and error and research I came across this post that solved my issue: https://discussions.apple.com/message/19084645#19084645

Long story short, running fsck_exfat on the Data partition (disk0s5) indicated that the main boot region needed to be updated and it provided an option to update it. Sure enough, this fixed it.

Prior to running fsck_exfat I tried the Verify Disk option on the partition in Disk Utility and it almost immediately failed saying "Invalid sector size: 0". Clicking the Repair Disk option failed and said the disk needed to be reformatted.

After running fsck_exfat and updating the main boot region Disk Utility still showed the partition as "disk0s5" rather than "Data". Clicking the Verify Disk option still gave there error saying the sector size was invalid, but the the partition name suddenly changed to "Data". Then, clicking Verify Disk again said everything was fine.

Hopefully this will help someone else out there. Or me, the next time I run into this...

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Theoretically everything is fine with your Fusion Drive. Fusion Drives look like this. Disk0 is your SSD with 121 GB and disk1 is your HDD with ~1 TB (~1.121 TB summed up).

The larger parts of your SSD (disk0s2) and your HDD (disk1s2) are pooled to a CoreStorage LVG (Fusion Drive: disk3) with a size of 967.8 GB. The rest is reserved for EFIs, a Recovery HD (alltogether ~1.3 GB) and your old Windows partition - now probably free space (~152 GB).

The logical volume 'Macintosh HD' (967.8 GB) spans disk0s2 and disk1s2. This is the first 'Macintosh HD' in picture 1. The volume 'Macintosh HD' - it's the one visible on the desktop - should ideally also have about 967.8 GB. This is the second 'Macintosh HD' in picture 1.
In fact it has only 852.67 GB (see picture 3).

In the second picture the logical volume 'Macintosh HD' is the first listed in black, the volume 'Macintosh HD' is the second listed in black, the other two 'Macintosh HD's listed in grey are the parts of your SSD and HDD dedicated to the logical volume 'Macintosh HD'.

In my opinion something went wrong after deleting various partitions with the Bootcamp Assistant/Disk Utility or in Windows.

Preparation:

Detach any external drive (especially your external Time Machine backup drive)
Restart to Internet Recovery Mode by pressing alt cmd R at startup.
The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
On a 50 Mbps-line it takes about 4 min (presenting a small animated globe) to boot into a recovery netboot image which usually is loaded from an apple/akamai server.

I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

Alternatively you may start from a bootable installer thumb drive (preferably Mavericks or Yosemite) or a thumb drive containing a full system (preferably Mavericks or Yosemite).

Now you may either repair CoreStorage or rebuild your Fusion Drive:

'Repair CoreStorage' (not recommended):

First i would try to check the volume 'Macintosh HD' with Disk Utility. If the volume is corrupted consider a reinstall of Mac OS X.
If the volume is ok quit Disk Utility
Open Terminal and enter diskutil unmountDisk /dev/LVIdentifier and both diskutil unmountDisk /dev/DiskContainingApple_CoreStorageIdentifier
In your case: first diskutil unmountDisk /dev/disk3 then diskutil unmountDisk /dev/disk0 and diskutil unmountDisk /dev/disk1
remove the EFI NO NAME partition with gpt remove -i IndexNumberOfEFINoName DiskIdentifier:
gpt remove -i 4 disk1
Remount the CoreStorage disks and then the Logical Volume:
In your case: first diskutil mountDisk /dev/disk0 and diskutil mountDisk /dev/disk1 and then diskutil mount /dev/disk3.

enter gpt -r -vvv show /dev/diskIdentfierOfApple_CoreStorage to get infos of your HDD CoreStorage disk.
In your case: gpt -r -vvv show /dev/disk1
It should look like this:

-bash-3.2# gpt -r -vvv show /dev/disk1
gpt show: /dev/disk1: mediasize=1000204886016; sectorsize=512;         blocks=1953525168
gpt show: /dev/disk1: PMBR at sector 0
gpt show: /dev/disk1: Pri GPT at sector 1
gpt show: /dev/disk1: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: /dev/disk1: GPT partition: type=53746F72-6167-11AA-AA11-00306543ECAC, start=409640, size=1671210848
gpt show: /dev/disk1: GPT partition: type=426F6F74-0000-11AA-AA11-00306543ECAC, start=1671620488, size=1269760
gpt show: /dev/disk1: Sec GPT at sector 1953525167                               
     start          size  index contents                                        
         0             1        PMBR                                            
         1             1        Pri GPT header                                  
         2            32        Pri GPT table                                   
        34             6
        40        409600      1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
    409640    1671210848      2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
1671620488       1269760      3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
1672890248     280634887
1953525135            32        Sec GPT table
1953525167             1        Sec GPT header

The free space on your HDD has 280634887 blocks. Please calculate the biggest block number dividable through 8. That's 280634880 blocks (á 512 bytes) which equals 143685058560 B or ~143.7 GB. Add the size of your HDD CoreStorage Physical Volume (852666400768 B) The result is 143685058560 B + 852666400768 B = 996351459328 B
Resize your HDD CoreStorage physical volume with diskutil cs resizeDisk HDDPVUUID newsize
In your case: diskutil cs resizeDisk 93892BE8-2B7F-4ABD-A4C3-984495DCD98D 996351459328b
Calculate the maximal size of your CoreStorage Logical Volume in diskutil cs list: (size disk0s2) + (size disk1s2) In your case that's 120988852224 B + 996351459328 B = 1117340311552 B. That should be the size of your refreshed Logical Volume Group.
Resize your Logical Volume with diskutil cs resizeVolume LVUUID LVGSize-128 MB In your case that's diskutil cs resizeVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0 1117212311552b. If you get an error (There is not enough free space...) choose a smaller size like 1117148311552b.
Quit Terminal and open Disk Utility.
Check your expanded CoreStorage Volume for errors.
Quit Disk Utility, choose your CS volume as startup disk and restart your Mac

'Rebuild Fusion Drive' (recommended if you have a Time Machine backup)

Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter:
diskutil cs list to get the CoreStorage listing.
Copy the Logical Volume UUID, it's the fifth listed.
Now delete the Logical Volume with diskutil cs deleteVolume LVUUID.
In your case: diskutil cs deleteVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0.
Copy the Logical Volume Group UUID, it's the first listed in the listing of diskutil cs list.
Then delete the Logical Volume Group with diskutil cs delete LVGUUID.
In your case: diskutil cs delete 1EFE58BC-3613-44C4-86EE-D816F3B66E3E
Enter exit and quit 'Terminal'
Open 'Disk Utility'. Enter 'Ignore' if you are asked to fix the drives.
Choose your SSD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~121 GB

Example:
Choose your HDD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~1 TB

Example:
Quit Disk Utility and open Terminal
Enter diskutil list

Example (your disk identifiers and sizes are different of course: Your volume SSD probably has the Identifier disk0s2 and the size 121 GB and your volume HDD probably has the Identifier disk1s2 and the size 1.0 TB):
Enter diskutil cs create "Name" IdentifierSSD IdentifierHDD
In your case probably diskutil cs create "Macintosh HD" disk0s2 disk1s2.

Copy the resulting LVGUUID

Example:
Enter diskutil cs CreateVolume LVGUUID jhfs+ "Macintosh HD" 100%.

Example:
Enter diskutil cs list
Check the size of your Logical Volume. It should have the size ~1.121 TB

Example:
Quit Terminal
Open 'Disk Utility' and check your newly created volume for errors
Quit 'Disk Utility'
Attach your external Time Machine backup drive or check this answer if you use NAS or another network share.
Open 'Restore from Time Machine Backup'
Choose the appropriate Time Machine backup and restore your system
Reboot to your restored system.
Unmount and detach your Time Machine backup drive
Open 'Terminal' and enter 'diskutil list'
Check if your 'Recovery HD' is listed.
If your 'Recovery HD' is missing, usually reinstalling your current system with the latest available system installer (e.g. 'Install OS X Mavericks (10.9.5)' if Mavericks is currently installed) will recreate it without loosing any data. AFAIK Recovery Partition Creator 3.8 will NOT create a Recovery HD on CoreStorage volumes.
After reinstalling the system with the latest available system installer open App Store and install the latest security fixes.

Best Answer

Related Solutions

MacOS – Shared data partition for Bootcamp no longer accessible

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

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