External hard disk can be detected but cannot be accessed

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.
On computer: TOSHIBA-MINCONG

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 ?

Update

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
                                 440DB97F-xxxx-xxxx-xxxx-19AEAC28E415
                                 Unencrypted
/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

Mincong Huang

Posted 2016-02-22T16:55:30.307

Reputation: 135

Please provide an English translation of the information you have provided. Verify you have authorization to plug this device into the computer, it is a trivial task, to configure Windows in such a way that unapproved storage devices won't be mounted. – Ramhound – 2016-02-22T17:04:36.057

It's almost certainly being disallowed from mounting. That said, what does diskmgmt.msc look like? – Ben N – 2016-02-22T17:08:25.057

I don't have access to diskmgmt.msc. It is restricted by a strategy. I need to call an administrator to do it. Let's give up this question and move on if you don't mind. @BenN – Mincong Huang – 2016-02-23T08:18:28.063

The disk seems to work perfectly, but the partition type for the second partition is ntot recognised. This means that windows does not recognise it and it cannot mount something it does not recognise.

Now on how to fix it. Step 1 would be te determine which filesystem it is. ext2? ext3? Reiser? some encrypted format? HFS?

After we know that we can continue to work to a solution. – Hennes – 2016-02-23T10:42:31.770

(continued). Since windows does not recognise it try booting another OS froma live CD (or pendrive). E.g. one of the many linux live CDs. Then do the modern equivalent of a fdisk -l). – Hennes – 2016-02-23T10:44:34.187

Try booting another OS from a live CD so that I can test the hard disk on Linux, is that what you mean ? @Hennes – Mincong Huang – 2016-02-23T10:57:25.930

Yes. Either if it recognises the format. Or see if it can spit out a partition type. (That type we then can decode here: https://www.win.tue.nl/~aeb/partitions/partition_types-1.html)

– Hennes – 2016-02-23T11:36:22.380

Answers

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

Gabe Zimbric

Posted 2016-02-22T16:55:30.307

Reputation: 70

select disk 2 followed by list partition would show whether the file system is recognized. – Ben N – 2016-02-22T17:28:58.243

If the file system was not being recognized the behavior would be entirely different. Based on the description the volumes are not even attempting to be mount – Ramhound – 2016-02-22T17:49:01.900

@Ramhound What kind of behavior would be happening then of the file system was unreadable? – Gabe Zimbric – 2016-02-22T18:59:04.873

@GabeZimbric link is dead. – Ted Taylor of Life – 2016-09-04T12:51:23.583

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.

Umar T.

Posted 2016-02-22T16:55:30.307

Reputation: 21

It is working elseo it could not comminicate with it, detect GTP partitioning and the EFI system partition. – Hennes – 2016-02-23T10:39:38.383

sorry mistyped!, I meant to test if the hdd case circuit is working, and not the hdd itself - already corrected my reply above. Since its possible that the system detects the hdd when connected through a malfunctioned case or connector but unable to read it. – Umar T. – 2016-02-23T11:07:52.303

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

Lex

Posted 2016-02-22T16:55:30.307

Reputation: 215

Option "Change Drive Letter and Paths" is disabled – Mincong Huang – 2016-02-23T09:14:44.517