What is a Partition Table and Where Is It on the Disk?
A partition is a part of the disk containing sectors and tracks inside. Partitions are displayed to the user because of the partition table. The partition table is located in the first sector (cylinder 0, head 0 and sector 1, MBR) of each hard disk. It contains information about each partition size and its location on the hard disk.
The partition information is started on offset 1BEH of the master boot sector. Each partition entry is 16 bytes long. The partition table is 64 bytes long in total. Thus, it can store only 4 partition entries. A partition table recovery tool is essential in case your data is lost or corrupted.
Fix Your Lost or Invalid Partition Table
If Windows refuses to boot up on your computer, its partition table might be missing or damaged. So, if you see the blue screen and a couple of pop-ups after you try to boot up your computer, don’t throw your computer into the trash can. Let’s try to repair the lost partition table first.
There is built-in utility software that comes free with your operating system to quickly help you to fix the partition table. Go through the steps below to fix the lost partition table yourself:
- Boot Windows using an installation disk. Go through the built-in instructions, wait approximately five minutes until Windows is booted up, and that is all.
- When Windows is ready, go to the command prompt and run it.
- To start the partition table repair process, type "bootrec.exe/fixmbr" in the command prompt and press "Enter". This command will perform a quick fix on the lost or damaged partition table.
There are several "bootrec.exe" commands available for different cases. For example, "bootrec.exe/fixmbr" can help if you see the "operating system not found" and "error while loading operating system" pop-ups.
How to Rebuild/Repair a Partition Table with Partition Recovery™
DiskInternals Partition Table Recovery™ tool deals perfectly with partition table failure. Below, we will look at a couple of common problems and ways to repair them.
When we try to boot testing procedures, we'll see a blank screen without any messages.
Solution: run DiskInternals Partition Recovery™ on another disk with Windows installed. It will automatically check and recover lost or damaged partition tables on the damaged disk.
My computer hasn’t found any active partition in the hard drive.
Solution: run DiskInternals Partition Recovery™ on the other disk with Windows installed. Connect the corrupted disk to recover the partition table with the help of the working one.
The partition table is invalid.
Solution: run DiskInternals Partition Recovery™, and you will see the following: “ERROR: Invalid Boot Indicator of primary partitions on Harddisk1. Do you want correct the error?” To recover the corrupted partition table, connect the second disk with Windows installed and run the DiskInternals Partition Recovery™ tool there.
Repairing Partition Table on Windows 7/8/10
How do you recover a partition table if you are not a specialist? There is a simple guide for how to restore a partition table. Go through it and complete the recovery process.
- 1. Install and run the trial version of DiskInternals’ Partition Recovery™ tool.
- 2. Run the initial scanning process. If the partition you need to recover hasn’t been identified automatically, you need to open the physical drive that has it by going: “Drives -> Physical drives”.
- 3. Wait until the list of recoverable files becomes available.
- 4. Preview files that are able to be recovered and purchase the licensed version of DiskInternals’ Partition Recovery™ tool if you want to save the found results.
- 5. Go through a couple of simple steps and wait until the partition table failure is resolved.
During this process, the Partition Recovery™ tool by DiskInternals will search for the deleted or lost partition tables located on the hard drive. In the trial version, it will show if it is possible to rebuild the partition table on Windows 7, 8 or 10, and then you can purchase the licensed version and complete the process.
If you need to go through many disks, restart the Partition Recovery™ Wizard by DiskInternals and go through each disk one by one.
Recovery MBR: Is It Worth It?
The MBR (“master boot record”) is a boot sector of your hard disk that holds information about the partitions on your hard drive and loads the operating system. MBR is created on the very first partition after Windows is installed. It’s the first 512 bytes of your hard disk.
If the MBR is damaged, you won’t be able to boot up Windows. This is true about all Windows versions. You can back up an MBR and restore it later if needed. To do this, go to the command prompt and enter the following:This command to list all partitions of drive 0:
MbrFix /drive 0 listpartitions
To back up the MBR of the first drive of the system in the file Backup_MBR_0.bin
MbrFix /drive 0 savembr Backup_MBR_0.bin
The command to restore the previously created master boot recorder backup to the drive
MbrFix /drive 0 restorembr Backup_MBR_0.bin
Even with the backups made, restoring your MBR with the wrong partition table will make your data unreadable and it will be very hard to recover a lost or damaged partition table later. So, if you need a reliable way to restore a corrupted partition table, you might need DiskInternals’ Partition Recovery™ tool. Try it and keep calm, even if your data is lost.