What should I do if the hard disk partition table is lost? How can I find the DiskGenius hard disk partition table when it is lost?

MBR partition table

The traditional partitioning scheme (referred to as MBR partitioning scheme) stores partition information in 64 bytes in the first sector (MBR sector) of the disk. Each partition item occupies 16 bytes, the 16 bytes contain activity status signs, file system IDs, start and end cylinder numbers, head numbers, fan area numbers, and hidden sector numbers (4 bytes), the total number of partitions (4 bytes) and so on. Since the MBR sector only has 64 bytes for partitioned tables, only information of four partitions can be recorded. This is the reason why the number of primary partitions cannot exceed 4. Later, in order to support more partitions, the concept of extended partitions and logical partitions was introduced. However, each partition item is still stored in 16 bytes.
The number of primary partitions cannot exceed 4. In many cases, the four primary partitions cannot meet the requirements. In addition, the most critical issue is that the MBR partition solution cannot support disks larger than 2 TB. This solution uses four bytes to store the total number of sectors of a partition. The maximum number of sectors is 2 to the power of 32. Based on the calculation of 512 bytes per sector, each partition cannot exceed 2 TB. After the disk capacity exceeds 2 TB, the start position of the partition cannot be expressed. Today, with the rapid development of hard disk capacity, the limit of 2 TB has already been broken. It can be seen that the MBR partition scheme can no longer meet the needs.

GPT partition table

A disk partition architecture used by the Extended Firmware Interface (EFI) on an Itanium-based computer. Compared with the primary startup record (MBR) partitioning method, GPT has more advantages because it allows each disk to have up to 128 partitions and supports a volume size of up to 18 Gigabit bytes, the partition table of the primary disk and the partition table of the backup disk can be used for redundancy. The unique disk and partition ID (GUID) are also supported ). The maximum supported volumes are 2 TB (terabytes) and each disk can have up to 4 primary partitions (or 3 primary partitions, 1 extended partition, and unlimited logical drives) the GUID Partition Table (GPT) disk partition style supports a maximum of 18 EB (exabytes, 1EB = 1024PB, 1PB = 1024 TB, 1 TB = 1024 GB, 1 GB = 1024 MB, 1 MB = kb. 18EB = 19 327 352 832 GB) and each disk has a maximum of 128 partitions. Unlike an MBR partitioned disk, the crucial platform operation data is located in the partition, not in a non-partition or hidden sector. In addition, GPT partition disks have redundant primary and backup partition tables to improve the integrity of the partition data structure.

What should I do if the hard disk partition table is lost?

DiskGeniusIt is best to use this software. It does not need to be installed and is also made in China.

Open the initial interface of DG (this is a screenshot of the repaired partition. Before the restoration, the e-disk displays the same information except the Unformatted information. Pay attention to the cylinder number of each partition, nothing found? Is continuous ):

1. during restoration, it is best not to copy the DiskGenius software to the hard disk on the computer for running. During the operation, data may be written to the hard disk. We recommend that you put DiskGenius in the USB flash disk, then insert the USB flash drive into the computer and run the software directly in the USB flash drive.

2. after DiskGenius is started, select "tools"> "search for lost partitions". If the data is deleted by mistake, select "tools"> "deleted or formatted file recovery ". This article focuses on the reconstruction of partition tables.

3. after you start searching, if you find a partition, you will be prompted to "ignore" or "retain". Note that the first result found is generally your system disk C, which cannot be retained, you must ignore it. Otherwise, you cannot find other partitions until you find the partition you want to restore and confirm that these files are saved in your other disks. (Actually, this is not absolute. From my personal data recovery experience, if you find a partition table result, the DG will also display the 45 GB data in this cylindrical range in the form of a windows browsing file, as shown in the figure below:

 

Check whether the data in disk C is exactly the data in disk C. If yes, the data will be retained. In this case, the DG will skip the detection of the 45 GB space, greatly saving the detection time.

Then proceed. In fact, the DG has started to detect the starting cylindrical (5888 cylindrical) of the D disk, and the DG has found 3 partition table information in the 5888 cylindrical, however, although the data sheet in the first result does not show the size of the partition, you can choose to ignore it.

 

If the second result is ignored, the partition size is not displayed.

When the third result is displayed, the partition table of the D disk is as follows:

 

At this time, I think the D disk is completely searched, because my D disk is 100.1 GB, and I checked the data in it. I chose to keep it.

If you get an alias for disk D, but it is not a "local Disk", the screenshot above does not show a "logical partition" but shows the alias you obtained, this is a useful piece of information.

After the data is retained, the DG directly jumps to the 18948 cylinder and finds a 100.1GB partition table. The prompt is unformatted partition ....

From the DG initialization interface, we can know that the 18948 cylinder is the ending cylinder of the D disk, and I have kept the partition table information of the D disk on the 5888 cylinder, this result means that the data in the partition cannot be viewed and displayed in the unformatted format. I chose to ignore it. In fact, I do need to ignore it because I choose to retain it, the DG directly ignores the detection of the E disk and jumps to the start cylindrical (37303) of F to start searching. If you select ignore, DG does not search for information about a partition table in the first cylindrical column of the e-disk, but in the 18949 cylindrical column, it searches for information about a partition table, the size of 130.4GB is exactly the size of the edisk. The data is still stuck in the edisk. I probably browsed the data and checked the complete data of several files.

(Note: This screenshot is my fixed screenshot. The content in the quotation marks in the screenshot shows the name of the edisk, rather than "unformatted (2 )")

Exciting ing! If you choose to retain the DG, you can directly jump to the starting cylindrical column (37303) of the drive F to continue searching. In fact, the lost data on the drive e is basically retrieved, after the partition table information of drive F is found, it is confirmed and retained. The partition table information of the entire hard disk is completely Retrieved. The whole process is not complicated, but be careful. Then you need to click the Save Change button in the upper left corner of the DG. DG will reset it for you Entire hard diskPartition information, note that Entire hard diskOh, if there is no problem with all operations, the system will immediately identify this partition after the DG resetting is complete.

 

4. After all the search is complete, click "Save changes" in the upper-left corner of the software ". After that, the computer may have a blue screen or crash. This is normal. Please press the power key to turn off the computer.

5. After the lost partition is retrieved, you need to repartition the hard disk and reinstall the system. At this time, you can use the "computer store USB flash drive preparation tool" to create a USB flash drive. First, partition the hard disk and then repartition It. Then you can reinstall the system.