MacOS – External disk – Unrecognized file system (-69846)

disk-utilityfilesystemhard drivemacosterminal

I have an external storage with 2TB that was working nicely. But since last week, when I unplugged the USB before eject it, the disk is not readable anymore.

When I insert USB, I can actually see this message box:

I also tried to repair it on Terminal:

diskutil unmountDisk force /dev/disk2
diskutil repairVolume /dev/disk2

That results on this error:

Error starting file system repair for disk2: Unrecognized file system (-69846)

Can anybody help me please?

EDIT

Terminal comand sudo gpt -r show /dev/disk returns:

gpt show: unable to open device '/dev/disk3': Resource busy

(even after umountDisk)

Terminal comand sudo fdisk /dev/disk returns:

Disk: /dev/disk3    geometry: 1003/16/63 [1011242 sectors]
Sector size: 4096 bytes
Signature: 0x0
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 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

Best Answer

Try this in the exact order:

#FOR THE WHOLE DISK
diskutil eject /dev/disk2               #Eject the disk 
diskutil mountDisk /dev/disk2           #Re-mount the disk

#FOR THE VOLUME(S) OF THE DISK
diskutil list                           #list volume identifiers. 
diskutil mount /dev/disk2sXXX           #Mount the Volume. Dont enter a disk ID
diskutil repairVolume /dev/disk2sXXX    #Repair the Volume. Dont enter a disk ID

Basically you are trying to correct previous mounting/ejection related errors by making sure the disk is safely ejected before you do anything else.

Once that is out of the way, have the disk re-mounted. Next, have the volume re-mounted. Finally, repair the newly mounted volume.

Additionally, double check for any human error. Did you want to repair the volume or the disk because you specified a disk identifier to repair a volume. You typed:

diskutil repairVolume /dev/disk2

it should be

diskutil repairVolume /dev/disk2sXXX

Or use repairDisk if you wanted to repair a disk.

Related Solutions

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.

MacOS – How to fix Mac hard drive partition showing as FDisk_partition_scheme

Please try the following:

Get the disk identifier of your external 3 TB drive
```
diskutil list
```
Below I assume the disk identifier is disk6
unmount the disk:
```
diskutil umountDisk disk6
```

Overwrite the first 40 blocks:

sudo dd if=/dev/zero of=/dev/disk6 bs=512 count=40

Create a new gpt:
```
sudo gpt create /dev/disk6
```

Check the disk info with:

diskutil info /dev/disk6

Reassure yourself that the device block size still is 512 Bytes

You may also use

sudo gpt -r show /dev/disk6

If the gpt shows:

   start        size  index  contents
       0           1         PMBR
       1           1         Pri GPT header
       2          32         Pri GPT table

you have a disk & disk controller which report a logical block size of 512 Bytes. Please continue with the next step.

If the gpt shows:

   start        size  index  contents
       0           1         PMBR
       1           1         Pri GPT header
       2           4         Pri GPT table

you have a disk & disk controller which report a logical block size of 4096 Bytes. Please stop here and add a comment.

First rebuild the EFI entry with:
```
sudo gpt add -b 40 -i 1 -s 614400 -t C12A7328-F81F-11D2-BA4B-00A0C93EC93B /dev/disk6
```
Depending on the size of the disk and the system version differently sized EFI volumes are built if partitioned with Disk Utility: either one with the size 200 MiB or one with 300 MiB. Here it's obvious that your disk contains a 300 MiB EFI and probably 4096 bytes of unallocated disk space: (314598400-1024)/512=614448 (=Start block main volume) 614448-40-8=614400 (=size of EFI)
Rebuild your main volume with:
```
sudo gpt add -b 614448 -i 2 -s SizeOfVolume1 -t 48465300-0000-11AA-AA11-00306543ECAC /dev/disk6
```
The size of the main volume can be determined by the first (corrupted & old) entry of the second GPT table: (3000592961536/512)=5860533128 is its block number. Then the size is calculated by 5860533128-614448=5859918680 blocks. Since 5859918680 is dividable by 8 (4096 physical block size/512 logical block size) this is a good guess for the volume size.

The best guess is finally:
```
sudo gpt add -b 614448 -i 2 -s 5859918680 -t 48465300-0000-11AA-AA11-00306543ECAC /dev/disk6
```
The second best guess is:
```
sudo gpt add -b 614448 -i 2 -s 5859918672 -t 48465300-0000-11AA-AA11-00306543ECAC /dev/disk6
```
Probably your lost volume gets mounted now. Verify the volume with:
```
diskutil verifyVolume disk6s2
```
If necessary try to repair the volume.
```
diskutil repairVolume disk6s2
```

Since you moved the "corrupted" disk to a different case and disk controller the logical block size was modified. The old partition map is probably based on a logical block size of 4096 Bytes.

To recover the partition map in the old (4096b) case you would had to enter the following to restore the GPT (based on David Anderson's answer):

Create a new gpt:
```
sudo gpt create /dev/disk6
```

First rebuild the EFI entry with:

sudo gpt add -b 6 -i 1 -s 76800 -t C12A7328-F81F-11D2-BA4B-00A0C93EC93B /dev/disk6

Rebuild your main volume with:

sudo gpt add -b 76806 -i 2 -s 732457067 -t 48465300-0000-11AA-AA11-00306543ECAC /dev/disk6

the final partition map looks like this:

 sudo gpt -r show disk1
       start        size  index  contents
           0           1         PMBR
           1           1         Pri GPT header
           2           4         Pri GPT table
           6       76800      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
       76806   732457067      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   732533873       32768         
   732566641           4         Sec GPT table
   732566645           1         Sec GPT header

Based on the 4096b part this "retranslates" after installing the disk in a 512b logical block size case to:

Create a new gpt:
```
sudo gpt create /dev/disk6
```