What is System Reserved partition and what is it used for?
Before learning the problem of System Reserved partition missing, you may need to know what the partition is and what the function of it is.
Since Windows 7, when you install Windows on a clean disk, a partition name System Reserved and about 100MB in size will be created at the beginning of the disk, and then the system drive and then other necessary drives. Usually, the System Reserved partition is 350MB in Windows 8 and 500MB for Windows 10. You can increase System Reserved partition when necessary.
System Reserved partition can be seen in Disk Management only because Windows does not assign a drive letter to it. It will not show up in File Explorer like other drives do to prevent stored files from deletion or modifying mistakenly. In general, the partition is consisted of two parts.
Boot manager and BCD file. When the computer starts, the Windows Boot manager reads data from the Boot Configuration Data (BCD) store and then starts the operating system from the system drive. It usually contains two folders, Boot and System Volume Information, and two files, bootmgr file and BOOTSECT.BAK file. That’s why you cannot boot up computer after the partition is missing.
The startup files used for BitLocker Drive Encryption. If you have the need of encrypting hard drive with BitLocker, Windows will be started from the files that stored the unencrypted System Reserved partition. And then decrypt the system drive and ensures successful boot.
After you aware of the importance of System Reserved partition and the role it plays, you can understand this context easier.
Problems with System Reserved partition missing
If you get System Reserved partition deleted, things will be serious. When the situation is not so bad, you may get backup failure in your schedule tasks. If things are terrible, you’ll find you cannot upgrade Windows 10 to latest Update and it says “Windows 10 couldn’t be installed. We couldn’t update the System Reserved partition.” If worse, you’ll find Windows cannot boot and with this message “Operating System not found” on the screen.
Error deletion is the most common reason for System Reserved partition not showing issue, but you may find it disappears after cloning from one drive to another. Maybe the partition is not cloned during the process or it may also be the partition is renamed or modified by the cloning software.
No matter what the cause is, you can find a way to fix this problem eventually.
How to recover System Reserved partition in Windows 7/8/10?
Note: data loss may be caused by inappropriate operations. Please perform a full backup before you start. If the system refuses to boot, please refer to backup hard drive without booting Windows.
In a nutshell, there are two ways to solve this trouble out. The first method does not need the help of third-party software and is to rebuild system partition, i.e. recreate the bootloader configuration. Here come the detailed steps.
Rebuild System Partition
This will need the assistant of Windows Installation Disc or similar bootable devices to help you enter into WinPE Command Prompt.
1. Boot up your computer from the Windows Installer. At the step of “Where do you want to install Windows”, press Shift + F10 to bring out Command Prompt.
2. At the prompt, to create the boot configuration file on a system drive instead of the System Reserved partition, input “bcdboot c:\windows /s c:” without quotes and hit Enter. You’ll see a return message: Boot files successfully created.
3. At the prompt, input “bootrec /fixmbr” without quotes and hit Enter.
4. Chances are that you’ll receive this error “Element not found” after the command. Then, you need to make the partition Active, using Diskpart. (If no error message received, skip to step 6.)
5. To make partition Active, please enter following commands successively.
6. Now, input these two commands to rebuild BCD file.
7. When it asks to add installation to boot, print Y and hit Enter. Then, you may leave Command Prompt and start your computer now.
If you do not have a Windows Installation disc, or you are not familiar with command line operations, you may want to take a look at the second method. It provides graphical user interface that is suitable for common users, and also command line operations for advanced users.
Recover lost System Reserved partition via professional tool
In detail, AOMEI Partition Assistant Professional will recover System Reserved partition if you delete it by mistake and fix boot issue if the master boot record is corrupted. It fully supports Windows 10/8/7, both 32bit and 64bit. Get it and have a try.
Notice: Since your computer cannot boot up normally, you need to create bootable media using the software on another well-function Windows-based computer. Then, boot up your computer from the bootable device. Following will take partition recovery for example.
1. Install and run AOMEI Partition Assistant on a work Windows PC. Insert a USB drive to the PC as well. In the software, click “Make Bootable Media” in the left pane. Follow the wizard to complete. Disconnect the USB drive.
2. Insert the bootable USB drive to your computer. Power on and press Del or F2 to enter BIOS. Change boot order to the USB drive and press F10 to save changes and leave.
3. Once login, you’ll see loaded AOMEI Partition Assistant software. Click Partition Recovery Wizard in the left side. Select a disk to recover in the pop up window.
4. Select a search method, Fast Search (recommended) or Full Search. It will start the scanning right after you click Next.
5. Select the deleted partition from the result and click Proceed to do the recovery. You’ll see “Congratulations!” information after. Click Finish to exit. Then, you can close this software and reboot your computer.
If partitions are not found by Fast Search, please select Full Search in step 5 and try again.
Partition Recovery Wizard supports recovering a basic disk with 512 bytes per sector and partitions formatted with NTFS or FAT32 file system only.
If there's a partition on the partition that you are going to recover, you may encounter the message saying the selected partition overlaps with the existing partition. To solve this problem, you need to delete the existing partition first through AOMEI Partition Assistant, and then use the partition recovery wizard to recover the partition.
If you want to fix boot issue of the system drive, please right click the disk, select “Rebuild MBR” to fix MBR without CD/DVD.
If you want to fix the System Reserved Partition missing on Windows Server 2008 R2, 2012 R2, SBS 2011 through the second method, please refer AOMEI Partition Assistant Server edition, a version designed for Server operating system in particular.
When you find System Reserved partition missing in Windows, you can rebuild the system partition with some command lines using Windows Installation Disc. Or, you can do partition recovery if you just format or delete the partition mistakenly. The recommended tool is also able to rebuild MBR portion to fix boot issue for your computer.
As you can see, AOMEI Partition Assistant can help you resizing C drive, allocate free space, move partition, merge partitions without losing data, migrate OS to SSD, convert MBR and GPT, secure erase SSD, etc. In other words, it manages your hard drive from all-round. Go for it and enjoy now.