Managing System Reserved Partition in Windows 10 | Windows OS Hub (2023)

During a clean OS install, Windows Installer creates a special System Reserved Partition (SRP) on the MBR disk partition table. This is a hidden partition with the NTFS file system, which is not assigned a drive letter by default, and doesn’t appear in File Explorer (most users don’t even know about the existence of this service SRP partition). In Windows 7/Windows Server 2008R2 the size of the System Reserved partition is 100 MB, in Windows 8.1/Windows Server 2012 R2 it is 350 MB, and in Windows 10/Windows Server 2016 it is increased to 500 MB.

In this article, we will figure out what the System Reserved partition is used for, whether it can be deleted and how to restore it if it has been deleted or damaged.


  • The System Reserved Partition in Windows 10
  • What is the System Reserved Partition Used for on Windows 10?
  • Can You Delete the System Reserved Partition on Windows 10?
  • How to Create a System Reserved Partition Manually in Windows 10?
  • Windows Can’t Boot after Accidentally Deleted System Reserved Partition
  • “Couldn’t Update the System Reserved Partition” on Windows 10

The System Reserved Partition in Windows 10

First, let’s see where the System Reserved partition is located and how to view its contents. Run the Computer Management mmc snap-in and select Storage -> Disk management. As you can see, in Windows 10, the 500MB System Reserved partition is in front of the system partition (C:\) where Windows is installed.

The following volume attributes are assigned to the System Reserved Partition: Primary partition, Active and System.

The System Reserved partition is only present on BIOS computers or UEFI devices that have the Legacy Compatibility Support Module (CSM) enabled. The MBR (Master Boot Record) partition table is used on the system disk of such computers. On computers with UEFI in native mode and GPT partition table, there is no SRP partition (the EFI partition is used instead).

By default, the System Reserved partition is not assigned a drive letter. You can set the drive letter through the Disk Management Console (diskmgmt.msc) or using the PowerShell command:

Get-Partition -DiskNumber 0 -PartitionNumber 1|Set-Partition -NewDriveLetter R

This is how the contents of the System Reserved volume look like (you need to allow showing hidden and system files in File Explorer):

(Video) How To Resize the disk | fix system reserved partition in windows 10

Note. If you are installing Windows to a disk with existing partitions, the installer doesn’t create a separate 500 Mb System Reserved partition. In this case the Boot Manager bootloader files are placed on the same volume where Windows is installed.

What is the System Reserved Partition Used for on Windows 10?

In earlier versions of Windows, boot files were stored on the partition with the installed OS. Starting with Windows 7, MSFT developers added a separate hidden System Reserved partition to store bootloader files. This solution helps to protect the bootloader files from users and improve the stability of Windows.

What is stored in the System Reserved partition?

  • Windows bootloader (bootmgr), and a file with the bootloader configuration BCD (Boot Configuration Data);

    Bootmgr replaced the old NTLDR bootloader in newer versions of Windows.

  • Service data of the BitLocker encryption subsystem (if used);
  • Windows Recovery Environment (WinRE) files that can be used to troubleshoot various boot problems;
  • System Volume Information folder for system recovery points metadata;
  • BOOTNXT – the file is used to boot Windows from USB flash drives (for example, for Windows To Go);
  • BAK – a backup of the boot sector used on MBR disks.

Can You Delete the System Reserved Partition on Windows 10?

You shouldn’t delete the System Reserved partition without a good reason, and even more so to save disk space (500 MB is not so much). Without this partition, your Windows won’t be able to boot, since the boot partition with the bootloader configuration is missing. An error may appears: “Operating system not found”.


File: \boot\BCDStatus: 0xc00000fThe Boot Configuration Data for you PC is missing or contains errors.

In this case, you will have to manually restore the Windows bootloader and place it on the system drive C: (described below).

How to Create a System Reserved Partition Manually in Windows 10?

If you deleted the System Reserved partition (or it is initially missing) and want to restore it, use the following steps.

Use the diskpart tool to shrink the Windows partition by 500 MB (in this example, we assume Windows is installed on the partition 1):

list volume
select volume 1
shrink desired=500

(Video) How to create Partition in Windows 10 | Disk Management windows 10 | Knowledge Hub

Create a new 500 MB NTFS partition:

create partition primary
format fs=ntfs
assign letter R

Now you can place the Windows bootloader files on the new partition:

bcdboot C:\windows /s R:
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd

However, in most cases, it is easier to move the bootmgr configuration to the Windows system partition (this is described in the next section of the article).

Windows Can’t Boot after Accidentally Deleted System Reserved Partition

If other partitions prevent you from shrinking/extending the Windows volume, you can restore the bootloader configuration and place it on the partition where Windows is installed. These steps will help you fix Windows boot after deleting a System Reserved partition.

You can make sure that the System Reserved partition is missing by booting from any Windows boot/installation media (USB flash drive or DVD). (In our case, it was the Windows Server 2012 R2 install media).

On the installation screen, press Shift+F10 to open a command prompt. Run diskpart and list the volumes:

list volume

As you can see, the System Reserved partition is missing, and of course, the Windows cannot boot from this disk.

In this case, to restore your system, you need to recreate the bootloader entries. In order not to create the separate 500 MB System Reserved partition, the bootmgr bootloader files can be re-created on a system drive C:\. To do it, run the following commands in WinPE command prompt. Place the boot environment files on drive C:\ and specify the path to Windows directory:

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bcdboot c:\windows /s c:

If successful, the command will return Boot files successfully created.

Now you need to overwrite the boot sector:

bootsect.exe /nt60 All /force

Tip. If the error “Element not found” appears, try to make system partition active using diskpart (described in the next step).

Then make the C:\ partition active. To do it, execute the following commands (you disk and partition numbers may differ, be attentive):

list disk
select disk 0
list partition
select partition 1

Tip. You should see the message “DiskPart marked the current partition as active


Then run these commands one by one:

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bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

The third command will scan all disks and try to find installed Windows copies (Scanning all disk for Windows installations). In our example, the OS has been found in C:\Windows folder. The system will ask to add these Windows entries to the boot list (Add installation to boot list?). Confirm it(Y).

Restart your computer and make sure that Windows is booted correctly. Make sure that bootmgr file is present in the root of the system drive C:\.

Tip. The steps for manually repairing the bootloader configuration on computers with the UEFI architecture are slightly different and described in detail in the article How to repair the EFI bootloader.

This manual also may be used to move Windows Bootloader configuration to different drive if the System Reserved partition is removed deliberately, when you want the system to be completely located on one partition (it is convenient from the point of view of some backup and disk management tools).

A complete guide on how to rebuild the BCD and MBR configuration is available in this article.

“Couldn’t Update the System Reserved Partition” on Windows 10

When upgrading from Windows 7/8.1 to Windows 10 (or when upgrading to new Windows 10 build), you may receive 0xc1900104 or 0x800f0922 errors:

Windows 10 couldn't be installedWe couldn't update the system reserved partition.

This is because the System Reserved partition is smaller in previous Windows versions than in Windows 10. And if the SRP is full and there is not enough free space (at least 15 MB) to place the Windows bootloader system files, you will get this error.

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In this case, Microsoft recommends deleting the font files from the R:\Boot\Fonts directory to free up space on the System Reserved partition( Or you can try to expand the System Reserved partition using any third party partition manager tool on a bootable USB stick.


How do I fix system reserved partition in Windows 10? ›

  1. Press the Windows key + R. ...
  2. Select the partition marked System Reserve. ...
  3. Select Change Drive Letter and Paths.
  4. Choose Add.
  5. Enter Y for the drive letter.
  6. Tap or click OK.
  7. From the Start menu, search for cmd. ...
  8. In the command prompt, type Y: and hit enter to switch to that drive.

How much should be system reserved partition for Windows 10? ›

The system reserved partition is created during the Windows installation process, which is about 100MB in Windows 7, 350MB in Windows 8, and 500MB in Windows 10.

How do I free up space on my system reserved partition? ›

To free up system reserved partition space, you can assign a drive letter to it in Disk Management and run “Disk Cleanup” on it. Open Disk Management, right-click the system reserved partition, select “Change Drive Letter and Path”, and follow the onscreen instruction to finish this operation.

Does Windows 10 need a system reserved partition? ›

The System Reserved partition is essential if you want to use BitLocker drive encryption, which can't function otherwise. Important boot files are also stored here by default, although you could store them on the main Windows partition if you prefer.

How do I free up system reserved storage in Windows 10? ›

You can see which features are installed on your device by going to Settings > Apps > Apps & features > Manage optional features. You can reduce the amount of space required for reserved storage on your device by uninstalling optional features you are not using.

What happens if we delete system reserved partition? ›

As we've explained above, Windows uses the System Reserved partition to store your critical boot files. Unless you specifically choose not to create a System Reserved partition when you install Windows 10, deleting the partition will break Windows and stop it from booting.

Can I increase system reserved partition? ›

Right-click on a redundant partition and select "Resize/Move Partition" to generate unallocated space. You can select C: drive or the drive after C. (As it only needs 400 MB at most, you can resize partition and generate some free space from C drive to make the System Reserved partition bigger.)

Should system reserved partition be active? ›

The partition flagged "active" should be the boot(loader) one. That is, the partition with BOOTMGR (and the BCD) on it. On a typical fresh Windows 10 installation, this would be the "System Reserved" partition, yes. Of course, this only applies to MBR disks (booted in BIOS/CSM compatibility mode).

What is the difference between system reserved and recovery partition? ›

Recovery Partition is the part of the drive to reset the machine back to how it was when you bought it. Windows creates a System Reserved partition when you install it on a clean disk. Windows doesn't assign a drive letter to these partitions, so you'll only see them when you use Disk Management or similar utility.

What files are in the system reserved partition? ›

The System Reserved Partition contains Windows RE files. In Windows 10, some files related to the recovery process are stored on this partition.

Is system reserved partition same as EFI partition? ›

If you see a 100MB system reserved partition, then you do not have an EFI partition and your computer is in legacy BIOS mode. If you had an EFI partition, both Disk Management and diskpart would tell you so. EFI partitions are found on GPT formatted drives and are used to boot the operating system.

Is it safe to delete system partition Windows 10? ›

All partitions except the EFI partition and the partition where the C drive resides can be deleted, but it is not recommended. I recommend compressing the space on the C drive to make room for other systems.

Should I hide system reserved partition? ›

System Reserved partition is essential which contains the Boot Manager, Boot Configuration Data and Startup files used for Bitlocker Drive Encryption. It is a good idea to hide System Reserved partition if you want others to stay away from it.

Why is my storage suddenly full Windows 10? ›

The possible causes can be: Too many applications or files saved on the disk. There is not enough disk space. File system corruption on the hard drive.

What is the purpose of the Microsoft reserved partition? ›

A Microsoft Reserved Partition (MSR) is a partition of a data storage device, which is created to reserve a portion of disk space for possible subsequent use by a Windows operating system installed on a separate partition.

Can you optimize system reserved? ›

Microsoft recommends that you do not optimize your Systems Reserved drive, as it is unnecessary. The partition being fragmented has no effect on performance. Your Systems Reserved drive's current status may be Needs Optimization, but Microsoft assures that it can be ignored.

Can I delete system reserved partition when reinstalling Windows? ›

But if the System Reserved partition doesn't contain any system boot components or information and you don't want this partition on your drive, you can delete it. However, you cannot use Windows Disk Management to delete this partition as Windows' protection mechanism command the tool not to delete this partition.

Can I copy system reserved partition to another drive? ›

Remember, the system reserved partition has to be a primary partition, if your new system reserved partition is a logical drive, then you should first convert it to a primary partition without losing data. Once you have completed this, you will have successfully moved the system reserved partition to a different drive.

Which partition does Windows 10 boot from? ›

The system partition (or system volume) is a primary partition that contains the boot loader, a piece of software responsible for booting the operating system. This partition holds the boot sector and is marked active.

What is the difference between the boot partition and the system partition? ›

A system partition stores files that are used to boot (start) the computer. These are used whenever a computer is powered on (cold boot) or restarted from within the operating system (warm boot). A boot partition is a volume of the computer that contains the system files used to start the operating system.

What happens if I delete the EFI partition? ›

Without the EFI partition, your computer won't be able to boot into Windows. In a word, EFI system partition deletion will cause the installed system unbootable. Therefore, EFI system partition is usually protected and locked by the Windows operating systems to prevent and avoid accidental deletion.

Is it OK to delete EFI system partition? ›

Can I delete EFI partition in Windows 10? You cannot delete EFI partition directly. This is because it is a protective system partition that stores the boot files. Deleting EFI partition will cause your computer to be unbootable.

Do I need both boot and EFI partition? ›

All systems with UEFI (as opposed to legacy BIOS) must have an EFI system partition in order to boot, however some Linux distros will choose to mount the files at some location other than /boot/efi , despite it being the most popular.

How do I restore system reserved? ›

Repair System Reserved Partition Windows 11/10 FAQs
  1. Boot your Windows computer via Windows installation media.
  2. Then in the first installation screen, press Shift + F10 keys to bring out the Command Prompt.
  3. Input the following commands and press Enter after each line of command. ...
  4. Type bootrec /fixboot + Enter .
Feb 22, 2023

Why am i unable to update to Windows 10 reserved partition? ›

One major reason that Windows 10 couldn't update the system reserved partition is that the system reserved partition is in low disk space for updating and installing the new system files. Therefore, to directly fix such a problem, you need to extend the system reserved partition space.

Why is system reserved drive showing? ›

As pointed out above, the system reserved partition shows up in File Explorer mainly because you assigned a drive letter to it. So, another method on how to hide system reserved partition is to remove the drive letter. Let's see how to remove a drive letter using Disk Management.

How to repair Windows 10 from BIOS? ›

To perform system recovery from the BIOS:
  1. Power on or restart the workstation.
  2. Enter the BIOS by tapping either the right or left bottom of the screen.
  3. Tap Advanced, and then tap Special Configuration.
  4. Tap Factory Recovery.
  5. Select Enabled from drop-down menu.
  6. Tap Home.
  7. Tap Save and Exit.

What do I do if Windows Startup Repair doesn't work? ›

What to Do if Startup Repair Fails to Fix Your PC
  1. Troubleshoot the Issue in Safe Mode. There might be an active background process interfering with the system's operation, which may explain why you're facing the problem. ...
  2. Rebuild BCD and Run CHKDSK. ...
  3. Restore the Registry Editor. ...
  4. Reset Your PC.
Oct 5, 2022

Is EFI system partition the same as system reserved partition? ›

If you see a 100MB system reserved partition, then you do not have an EFI partition and your computer is in legacy BIOS mode. If you had an EFI partition, both Disk Management and diskpart would tell you so. EFI partitions are found on GPT formatted drives and are used to boot the operating system.

What is the OEM reserved partition in Windows 10? ›

OEM partition is designed for system recovery or factory restore. It allows users to easily and quickly restore the system to the original state when system failure or system crash occurs. This partition usually comes with Dell, Lenovo, or HP computer. The OEM partition is also known as a recovery partition.

Is system reserved partition necessary? ›

The System Reserved Partition stores BitLocker files. You can't use BitLocker encryption without the System Reserved Partition. This is because the startup files used for BitLocker are stored on this special partition — they can't be stored anywhere else.

Why is my reserved partition not showing up in Disk Management? ›

If the “System Reserved Partition not showing in Disk Management” issue is caused by the missing Boot Manager, it may indicate the BCD files in your Windows 10 are corrupted or missing. In this case, you should try to fix this issue by rebuilding BCD.


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