External hard disk can be detected but cannot be accessed

Posted on


I’ve plugged an external hard disk on my computers. The device has been detected, but isn’t shown on explorer. It is the same situation on both windows 7 and windows 10.

Detected / installed because it was shown in control panel > Devices and Printers. Also because I’ve found it using the list disk command line and it should be the Disk 1 :

Microsoft DiskPart version 10.0.10586

Copyright (C) 1999-2013 Microsoft Corporation.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          238 GB      0 B        *
  Disk 1    Online          465 GB   127 MB        *

Unrecognized because it seems that the Partition 2 has unknown file system type. So it cannot be recognized by windows.

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    System             200 MB    20 KB
  Partition 2    Unknown            465 GB   200 MB

Can somebody help me to resolve this problem without clean the data in the hard disk ?

Disk manager Toshiba


I tested the hard disk format type on OSX. And its type Apple_HFS as you can see at /dev/disk2.

Air-de-xx:~ xx$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Macintosh HD            120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +120.1 GB   disk1
                                 Logical Volume on disk0s2
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS MEMUP                   499.8 GB   disk2s2


What was the hard drive used for previously? Make sure the hard drive is formatted in NTFS, Fat32, or eXFat so that it is readable by Windows. Windows can’t read file systems that are formatted for Mac or Linux. It may also not be mounted.

Guide to mount drives: http://windows.microsoft.com/en-us/windows/mount-dismount-drive#1TC=windows-7

Try changing the external hard-disk case or plug it in through another external USB hard-disk connector (and not through its own case circuit), to make sure if the hard-disk case circuit is still working and not gone out of order.

Please check the disk manager. There are multiple ways to access it, and depending on the version of Windows that you have, the steps might be slightly different

On most windows
1. Open Windows Explorer > Right-click My Computer/or This PC > Manage
Or WindowsKey + R > Type diskmgmt.msc
2. Locate the disk partition in question > Right-click “Change Drive Letter and Paths”
3. Make sure there is a drive letter associated to the disk, or click Add to create one
4. See if you can access the disk after a disk letter had been established

Here is a quick example to Win7 steps
enter link description here

Leave a Reply

Your email address will not be published. Required fields are marked *