Hard Disk Partitions not Readable/Detected-Cause and Remedy

Hard disk partitions are nothing but a way to organize the physical space on your hard disk. Partitions allow you to split your HDD into multiple drives. The information about these partitions is stored in a file system known as Partition table. By information we mean that it stores the starting and ending point of partitions, name, size and other related details about HDD partitions. But at times while working on a system when you try to open one of the partitions you may end up in finding nothing in it. The partitions are either not detectable or are not readable. This proves to be very fatal case when a crucial amount of data is stored in the same partition(s).

Conditions For Partitions To Be Visible

For the partitions to be detectable to the user the following conditions should be satisfied:

• Partitions can be found by the partition table
• Partition boot sector is safe

Scenarios When The Partitions Is Not Available

There are many scenarios when one experiences this issue. Let us see each one of them.

• This issue can sometimes occur in multi-boot setups. Suppose, you have made a partition in your hard drive for Windows 7 while the operating system on which you are working is Windows 8. You succeed with the installation of both the operating systems without any problem. However, the issue arises when you boot Windows 8 and the only partition visible to you is the one that contains Windows 7.
• The recovery partition is empty and no letter is assigned to it. You decide to use it to store the image backup of current state of your Windows. But the partition is not getting detected by any of the Windows software also.
• At times when you connect an external HDD it is not detected by the computer and shows no drive letter and unallocated space.
• In worst cases the system refuses to boot and displays messages like “Bad or missing partition” or “Error loading operating system”.

What Are The Reasons Behind The Issues?

If you are experiencing any of the above mentioned situations then it can be said that either you have deleted the partitions accidentally or they have got damaged. Some of the reasons that lead to an unavailable disk partition or an unallocated space are listed below:

• Most HDD partition issues are caused due to MBR damage in the partition table. This can happen in absence of the disk signature (0x55AA).
• There are chances that the boot sector of a primary volume is damaged.
• If your system has FAT32 file, maybe the backup boot sector is damaged along with the boot sector of primary volume.
• Partition chain corruption where the logical drives get lost as soon as first link among the MBR gets broken.
• At times it is possible that you have not properly partitioned the drive using the disk editor utilities available due to which they tend to become unreadable.

Recovery Of Unreadable Partitions?

Whether you confront the detectability issues due to partition table corruption or due to boot sector damage it becomes urgent to recover the partitions. If the partitions are lost due to partition table corruption or accidental deletion issues, the partitions may not be visible to you. But in reality the allocated space is still available which makes the chances of recovery high.

NOTE: After the HDD partition is lost make sure not to create a new partition on the unallocated space created. If a new partition is created and any data is written to it, it will lead to over writing of the undetectable partition. As already told above, the partition table does not get deleted permanently. Therefore, overwriting the partition would lead to permanent partition and its data loss.

How To Restore The Undetected Partitions?

As mentioned above the reasons which contribute to the partitions being not readable can be partition corruption or unintentional deletion. Thus, recovering these partitions becomes a mandatory need for the user.

1. Damaged MBR

   The Master Boot Record contains the partition table and a small amount of executable code for boot start. A simple way to recreate MBR is to run Microsoft’s standard utility Fdisk with a parameter /mbr. The command used to run this command is:
   A:\>FDISK.EXE/MBRWarning: Do not use this command in case your system has more than 4 partitions or some dual-boot programs are in use.Note:

   a) You can only employ this command to operate on system drive (DISK-0)

   b) Applicable on MS Windows 98.

2. If Partition Boot Sector Is Damaged
   For our first NTFS partition we have a boot sector. You can employ following ways if this partition gets damaged:
   a) If we have the backup of the whole disk or MBR/boot sector we can restore it.
   b) In case the backup is not present you can try to locate a duplicate copy of partition boot sector and get the required information.

 

1. Corrupted or Missing System Files
   For proper operation of Operating system, the system files need to be safe. To detect whether the files are safe or not you can take help of Recovery Console. It is command line utility used for administrative tasks. To run this utility you can follow the mentioned steps:
   a) Boot from Windows bootable disk or CD and choose repair option.
   b) When system suggests you to proceed with the installation click on C to run Recovery console.
   c) You will be asked about the system you want to log on and then you need to enter Administrators password.
   Now you can easily view the drive’s contents and check if the files are available or not.

 

1. In case you are using an external HDD remove it from the system where the partitions are not readable. Connecting HDD to a different system will help.
   Note: This method applies to Windows NT, Windows 2000, and Windows XP.

Third Party Recovery Software

The methods described above need technical precision and the user to be very careful while applying them as even a slight mistake can ruin the situation more. To get guaranteed results, you can take help of Hard Disk Data recovery software. With the help of this commercial software you can easily recover data from a corrupt logical partition. The software can recover the corruptions caused even due to MBR and MFT damage. To recover the partitions in case of MBR damage, the involved hard drive needs to be detached from its respective system and attached to a working computer. This will make the HDD readable for the machine as well as the software to perform the recovery.