Windows System Partition Missing-How to Recover?

System partitions missing in Diskpart

A Windows system partition is a primary partition that contains Windows Boot Manager, and Boot Configuration Data(BCD). It means if you accidentally deleted the Windows system partition or the system partition is missing, the computer won't boot normally.

Usually, there are two types of Windows system partition. EFI System partition and System Reserved partition. If your hard drive is a GPT-based disk, it must contain an EFI System partition to boot Windows. It occupies 100 MB in Disk Management. System Reserved partition is created when the operating system is installed in an MBR-based drive.

If the EFI system partition or System Reserved partition is accidentally deleted or missing, how to recover it? Check the solutions in the following to recover or fix deleted/missing Windows system partitions.

How to recover the missing Windows system partition?

To recover the missing Windows system partition, you have two solutions to choose from. If the data stored in the local boot partition (usually C: drive) is not important, you could reinstall the Windows operating system. Windows system partition will be created once the Windows operating system is installed.

If you don’t want to lose the data in C: drive, you could first detach your hard drive and connect it to a healthy computer to back up your data, and then reinstall the Windows.

Recover missing Windows system partition via partition recovery software

Compared with reinstalling the Windows operating system, using a professional partition recovery tool is easier to operate for everyone. It’s recommended to use AOMEI Partition Assistant Professional to make a bootable USB disk and recover the missing Windows system partition via Partition Recovery Wizard, a built-in function in AOMEI Partition Assistant Professional.

AOMEI Partition Recovery Wizard is created to help users recover the deleted or lost partitions in Windows 7/8/10/11/Server. It not only supports NTFS partition recovery but FAT, Ext2, Ext3, and Ext4. Download AOMEI Partition Assistant Professional Demo and follow the steps below to create bootable media and recover the missing partition.

AOMEI Partition Assistant is an outstanding partition manager. It allows users to manage the partitions easily. It provides basic partition management functions: resize/move partition, merge partitions, split partition, allocate free space, create partition, etc. 

Moreover, it is an all-around converter and wizard. It is MBR/GPT disk converter, dynamic/basic converter, NTFS/FAT32 converter, etc. It has Windows to go creator, partition recovery wizard, secure erase Wizard, disk clone wizard, etc.

Stage 1. Making a bootable USB disk

Step 1. Prepare an empty USB drive to a healthy Windows computer, install and launch AOMEI Partition Assistant Professional on it. Click “Make Bootable Media” on the left panel of the main interface. Click “Next”.

Step 2. Choose “USB Boot Device” in the following window and click “Proceed” to start the operation.

Step 3. Click “Yes” to confirm formatting the USB drive to make the bootable disk. When the process completes, the bootable USB disk is ready to recover the missing Windows system partition. AOMEI Partition Assistant will be pre-installed on the USB drive.

Stage 2. Recover Windows system partition via partition recovery software

Step 1. Connect the bootable USB disk to the computer that can’t boot. Boot the computer and press the Del key to enter BIOS and change the BIOS boot priority to start it from the USB drive. The AOMEI Partition Assistant will start automatically when you log in.

Step 2. Click “Partition Recovery Wizard” on the left panel, and choose the hard drive which contains the Windows system partition. Click “Next”.

Step 3. Choose a search mode. Try “Fast Search” to save time. If the Windows system partition couldn’t be found, use “Full Search”.

Step 4. After the search process completes, select the missing Windows system partition in the list and click “Proceed”. When the partition recovery is done, the computer will boot normally again.

How to fix “a required partition is missing”?

Sometimes, users may encounter this error “Unable to reset your pc. A required partition is missing.” It usually appears when the MBR (Master Boot Record) or BCD (Boot Configuration) has corrupted or something wrong with your computer disks. You could run Bootrec Command to rebuild BCD or repair corrupted MBR.

Method 1. Fix partition missing via CMD

To fix the "Unable to reset your PC. A required drive partition is missing" error in your Windows 10 computer, you have to correct the MBR or BCD file. You need to prepare a Windows 10 installation DVD or USB flash drive first.

Step 1. Insert the Windows 10 installation DVD or USB flash drive into your computer.

Step 2. Boot into Windows 10 system recovery options, choose “Troubleshoot”> “Advanced options”>“Command Prompt”.

Step 3. Enter the following command in turn.

bootrec /scanos

bootrec /fixmbr

bootrec /fixboot

bootrec /rebuildbcd

Solution 2: Rebuild MBR with AOMEI Partition Assistant

Step 1. Make a bootable USB drive and change the BIOS priority to boot the computer from the USB disk.

Step 2. Right-click the system hard drive on the main interface and select “Rebuild MBR” in the drop-down menu.

Step 3. Set the type of MBR according to your Windows operating system, then click “OK” to proceed.

Step 4. Click “Proceed” and “Apply” to confirm the operation.

Conclusion

If you accidentally deleted the Windows system partition, you could use AOMEI Partition Recovery Wizard to restore accidentally deleted or lost boot partitions in Windows. For the missing Windows system partition due to MBR or BCD corruption, rebuilding BCD via command or rebuilding MBR via AOMEI Partition Assistant is a good way to fix the error “Unable to reset your pc. A required partition is missing”.

Of course, to avoid partition and data loss, the best way is to use Windows backup freeware-AOMEI Backupper to back up important data, partitions, and systems.