After opening Windows Explorer we may find one of partitions disappeared and became unallocated space in Disk Management, which we called partition loss. When we try opening a certain partition, Windows asks us to format it or says it does not contain a recognized file system. At this time, we say the partition has been logically damaged. Partition loss and partition damage are 2 kinds of partition errors we often meet. In this post we will make a brief introduction to these partition errors as well as show some solutions.
1.Factors Which May Result in Partition Loss
There are lots of reasons which can cause a partition lost, including:
We delete the partition(s) by mistake when managing partitions in Disk Management or Diskpart.
Virus like boot sector virus deletes the partition(s) maliciously.
Sudden power outage damages partition(s).
Mistakenly clone a partition to the entire hard disk or restore the image to entire disk.
Poor partitioning software brings damage to partition(s).
2.The Essence of Partition Loss
Actually, though a partition is missing from both Windows Explorer and Disk Management, it still exists before new partitions are created. At this time, we believe some users would feel confused: why a missing partition exists. To get rid of this puzzle, let’s see something about partition table.
Currently, there are 2 kinds of partition table, namely MBR partition table and GUID partition table:
MBR Partition Table
GUID PT Partition Table
On the screenshots above, areas boxed by red line are master partition table areas (the first partition table). Master partition table on MBR disk is different from that on GPT disk:
Master partition table on MBR disk: MBR boot sector is the first sector (absolute 0 sector) of hard disk and consist of 3 parts, including 446 bytes bootstrap code area, 64 bytes master partition table, and 2 bytes boot signature. MBR master partition table describes information of all primary partitions, including partition file system, partition type, starting sector, ending sector, total sectors in a partition (partition size), and so on. If there is an extended partition (a special primary partition which will be introduced later), there will be an entry pointing to extended partition. However, since there are only 64 bytes for master partition table and every entry of primary partition takes up 16 bytes, there are 4 entries in total. That is to say we are only allowed to create 4 primary partitions or 3 primary partition and one extended partition on MBR-formatted hard disks at most.
Actually, apart from master partition table, there are extended partition tables on MBR disk. In order to create more than 4 partitions, Microsoft introduces extended partition. Extended partition is a special primary partition where multiple logical partitions can be created. Every logical partition has an extended boot record (EBR) which functions like MBR and contains an extended partition table. And every partition table ends with 55AA signature no matter it is master partition table or extended partition table.
Master partition table on GPT disk: a GUID partition table can range from LBA 2 to LBA 33 (logical block addressing) and contains up to 128 partition entries, which shows users can create up to 128 partitions on a GPT formatted hard disk. And there is a master partition table backup at the end of the disk, which functions when the source failed. Each entry also records partition type, first LBA, last LAB, partition attributes, partition name, etc. GPT master partition table records attributes of all partitions.
Actually, every partition has its own partition table, not limited to master partition table. Partition table of the first partition records information of the first partition, and at the same time gives information to figure out parameters of the second partition, which makes it possible to recover lost partitions.
Commonly, what we or viruses operate is partition table rather than the real partition. When information which can locate a partition is modified or cleaned in partition table, Windows will be unable to find it so that we cannot see it. At this time, we say this partition is missing. Under this situation, as long as we fix or restore partition table to its original state with partition recovery tools, lost partitions can be recovered. In this post, we mainly introduce 2 programs, namely Winhex and MiniTool Partition Wizard.
How to Recover Lost Partition with Winhex
This is my current partitions (the disk is formatted with MBR):
And I decide to delete partition H and then use Winhex to recover it by fixing partition table in MBR sector.
Firstly, we need to download or purchase Winhex tool, and then install it on computer in accordance with prompts. After that, run it to get its main interface:
Next, choose a specified disk to open, and then the following window will appear:
From the left bottom of the window we know there are 503,316,480 sectors in this drive, and we are in the absolute 0 sector (sector 1) now, which is the sector where master boot record, and master partition table resides. In my demonstration, I’m going to fix master partition table to restore lost partitions. Since any minor damage to MBR may cause Windows unbootable, we had better back it up.
Steps to Backup MBR sector
1. Right click the offset first byte of sector 0 and choose “Beginning of block”.
2. Go to the last byte of the 0 sector. Then, right click it and choose “End of block”.
Note: all sectors are separated by a line. AA is the last byte of sector 0, and the byte after 55 AA is the first byte of sector 1.
3. After these operations, all bytes in sector 0 will be selected. At this time, right click the selected area and choose “Copy Block → Normally” command.
4. Go to any sector which is empty, and here we choose sector 1. Right click the offset first byte of sector 1 and choose “Edit”.
5. Choose “Clipboard Data → Write” command.
6. Now we can see sector 0 has been copied to sector 1:
After that, we can go to MBR sector namely sector 0 to repair master partition table.
Steps to Fix Master Partition Table
Firstly, we need to click “View” icon on the top and choose “Template Manager” in the MBR sector namely absolute 0 sector.
Then, please select “Master Boot Record” and click “Apply” to get the following window:
Now we can see all parameters in the third partition entry is modified to 0, which shows this partition gets lost. At this time, as long as we restore these parameters, the lost partition can be recovered. Well then, how can we know the original partition parameters? Actually, we can figure them out via other partitions’ information.
From the first partition entry we know there are 2048 sectors before partition 1, and partition 1 contains 42,430,464 sectors. That is to say the lost partition starts from 42,432,512 (42,430,464 + 2048) sector. From the second partition entry we know there are 93,712,384 sectors before partition 2, so there are 51,279,872 (93,712,384 - 42,432,512) sectors between partition 1 and partition 2, and these are sectors occupied by partition 3, namely the lost partition. If you are confused, please see the following chart:
After getting these data, we can restore the third party entry:
After that, close this window and confirm the changes to MBR.
At last, shut down Winhex and confirm operations. After these operations, we can see the missing partition is recovered:
Note: If Windows fail to boot due to the loss of system partition or boot partition, users have to take out the disk and do partition recovery in another computer or make a bootable Winhex. For how to burn an image, please see Burn a CD or DVD from an iso File.
However, though the lost partition can be recovered via repairing partition table, operations are so complex that common users have big difficulties in mastering it. In addition, if both master partition table and other partition tables are damaged, partition recovery will be much more difficult, because they need to repair every damaged partition table respectively. Moreover, Actually, the partition recovery software MiniTool Partition Wizard can make it quite easy to fix partition table, and users only need to click mouse for several times. Here are detailed steps.
How to Recover Lost Partition with MiniTool Partition Wizard
Firstly, download and install the partition recovery software to computer. Then, run it to get the starting interface and choose “Launch Application” module to launch it.
This is the main window of MiniTool Partition Wizard. To recover a missing partition, please select the disk where partition loss appears and choose “Partition Recovery” module from the left side.
Then, set scanning range for the selected disk and click “Next>”. If you haven’t created any partition after the partition gets lost, choosing “Unallocated Space” is a good choice, because it avoids scanning unnecessary area.
Next, choose a scanning method and click “Next>”. Then the partition recovery software will scan the specified range automatically. After scan both existing partitions and lost partitions will be listed:
Now please check all needed partitions (unchecked partitions will be lost no matter it is lost or existing now) and click “Finish”.
Now we can see the lost partition is recovered but does not have a drive letter. Please select the recovered partition and choose “Change Drive Letter” to appoint it with one. At last, click “Apply” button on the top to make all changes performed.
After application we can see the lost partition is recovered. It is so easy, right? If we want to recover missing partitions when Windows cannot boot, MiniTool Partition Wizard Bootable CD (an iso file) is available. Detailed steps are as follows:
1. Download the iso file and then burn it to CD or DVD.
2. Put the bootable disc to CD driver to boot computer.
3. Fix partition table in accordance with operations shown in the above content.
Of course, you can also connect the target disk to the computer which is running normally, and then do partition recovery by using MiniTool Partition Wizard.
Next, let’s see another partition error – logical partition damage.
When we try opening a partition or external device, like USB flash drive, CF card, and SD card, Windows may ask us to format it. Or a certain device is shown as RAW. Or we cannot access a device though it exists. When your device is under such circumstances, we say it is logically damaged. Actually, it is the damage of file system most of the time.
Factors Which May Cause Partition Logically Damaged
These kinds of errors may emerge after the following situations:
1. Plug external devices or hard disk when it is working.
2. Accidental shutdown.
3. Virus attack.
4. Mistaken operation.
The Best Way to Recover Logically Damaged Partition
To fix these issues, we only need to repair the file system, and formatting command can solve the problem. However, formatting a device will make all files saved in the partition or device lost. So is there a way to fix the damaged partition without losing any data? That is to recover lost data before formatting. Both Winhex and professional data recovery software can help do data recovery, but the former tool requires more complex operations than those for partition recovery, so here we mainly recommend data recovery program.
How to Recover Lost Data from Damaged Partition
As long as we restore data from the logically damaged partition at first, there is no need to worry about data loss whenever we delete or format the drive. And data recovery software can help complete the recovery very easily. Here, we take MiniTool Power Data Recovery for example to show specific operations.
Firstly, launch the program to get its main interface:
Then choose “Damaged Partition Recovery” module since it aims at recovering data from logically damaged partition.
Next, select the damaged partition to scan (both “Open” and “Full Scan” are available).
Then, check all needed files and save them to another device or partition.
When the logically damaged external device or partition is reformatted, transfer the recovered files to the repaired device. And now we can say partition recovery in Windows is done without data loss. For detailed information about this kind of recovery, please see Damaged Partition Recovery.