Why Reserved Storage Allocates 9 GB on a 256 GB Drive on Windows 11

You open File Explorer and see that Windows 11 reports only 247 GB of usable space on your 256 GB drive. The missing 9 GB is not a hardware defect or a hidden partition. This space is allocated to a feature called Reserved Storage, which sets aside disk space for system updates, temporary files, and optional features. This article explains why Reserved Storage claims 9 GB on a 256 GB drive, how the size is calculated, and how you can verify or adjust this setting.

How Reserved Storage Works on Windows 11

Reserved Storage is a feature introduced in Windows 10 version 1903 and carried into Windows 11. It sets aside a portion of disk space that only the operating system can use. The primary purpose is to guarantee that Windows Update always has enough free space to download and install feature updates, quality updates, and driver updates. Without Reserved Storage, a nearly full drive can cause an update to fail, leaving the system in an incomplete state.

The feature also reserves space for temporary files used during update installation, for system caches, and for optional features you may enable later such as Windows Sandbox or Hyper-V. By keeping this space available, Windows 11 avoids the need to delete user files or applications to make room for an update.

Reserved Storage is enabled by default on all installations of Windows 11, regardless of drive size. The amount of space reserved is not a fixed number. It changes based on the size of the drive, the current version of Windows 11, and the optional features installed.

Why 9 GB on a 256 GB Drive

On a 256 GB drive, Windows 11 typically reserves between 7 GB and 9 GB. The exact number depends on the build version of Windows 11. For example, on Windows 11 version 22H2, Reserved Storage is approximately 7 GB. On version 23H2, it can increase to 8 GB or 9 GB. Microsoft adjusts the reserved size with each feature update to account for larger update packages and additional system files.

The drive size also influences the reserved amount. On smaller drives, such as 64 GB or 128 GB, Windows 11 reserves a smaller percentage of the total space. On drives 256 GB and larger, the reserved amount scales up but stays within a range that ensures updates can complete without user intervention.

How to Check Reserved Storage Size on Windows 11

You can verify how much space Reserved Storage is using on your system through the Settings app. Follow these steps to see the exact number.

1. Open Settings
   Press Win + I to open Windows Settings. Select System from the left navigation pane, then click Storage.
2. View storage categories
   Under the Storage management section, click Show more categories. A list of storage categories appears, including System & reserved.
3. Check System & reserved
   Click System & reserved. The Reserved Storage line shows the current size used by the feature. On a 256 GB drive, this number is typically between 7 GB and 9 GB.
4. Expand details
   Click the Reserved Storage row to see a breakdown. Windows 11 shows how much space is reserved for system updates, system caches, temporary files, and optional features.

If the reserved space is larger than expected, you can run Disk Cleanup to remove old update files and reduce the reserved amount temporarily. Open Disk Cleanup by typing cleanmgr.exe in the Start menu, select your system drive, click Clean up system files, and check Windows Update Cleanup. This can free several gigabytes of reserved space.

Can You Disable Reserved Storage on Windows 11

Yes, you can disable Reserved Storage by editing the registry. Microsoft does not provide a toggle in the Settings app for this feature. Disabling Reserved Storage is not recommended for most users because it removes the safety buffer that ensures updates install correctly. If your drive is nearly full and an update requires more space, the update will fail and may leave the system in an unstable state.

If you choose to proceed, follow these steps. Back up your registry before making changes.

1. Open Registry Editor
   Press Win + R, type regedit, and press Enter. Click Yes in the User Account Control prompt.
2. Navigate to the Reserved Storage key
   Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ReserveManager. If the ReserveManager key does not exist, right-click CurrentVersion, select New > Key, and name it ReserveManager.
3. Create a new DWORD value
   Right-click in the right pane, select New > DWORD (32-bit) Value, and name it ShippedWithReserves. Set its value to 0.
4. Restart your computer
   Close Registry Editor and restart Windows 11. After the restart, Reserved Storage is disabled. The space it previously used becomes available for other data.

To re-enable Reserved Storage, change the ShippedWithReserves value to 1 or delete the DWORD value entirely.

Common Issues with Reserved Storage on Windows 11

Reserved Storage Is Larger Than Expected After a Feature Update

After installing a feature update like version 23H2, Reserved Storage may temporarily increase to 10 GB or more. This happens because the update keeps old system files for ten days to allow rollback. The reserved space returns to its normal size after the cleanup period ends. You can manually remove old update files using Disk Cleanup to reclaim the space immediately.

Reserved Storage Shows 0 Bytes but Drive Is Still Low on Space

If Reserved Storage shows 0 bytes in Settings, the feature may be disabled, or the drive may be too small for the feature to activate. On drives smaller than 32 GB, Windows 11 may not enable Reserved Storage. The low disk space is caused by other system files, page files, or user data. Check the System & reserved category for a full breakdown of what is using space.

Cannot Disable Reserved Storage Because Registry Key Is Missing

On some Windows 11 builds, the ReserveManager key does not exist by default. You must create it manually. If the ShippedWithReserves DWORD is also missing, create it as described in the steps above. If the registry change does not take effect, verify that you are editing the correct hive and that you restarted the computer.

Reserved Storage Size Comparison Across Windows 11 Versions

Item	Windows 11 22H2	Windows 11 23H2
Description	Feature update released in September 2022	Feature update released in October 2023
Reserved Storage on 256 GB drive	Approximately 7 GB	Approximately 8-9 GB
Update package size	Smaller cumulative updates	Larger cumulative and feature updates
Optional features included	Basic set	Expanded set including Copilot and new widgets
Disk Cleanup reduction	Can reduce to 4 GB after cleanup	Can reduce to 5 GB after cleanup

Reserved Storage is a built-in safeguard for update reliability. The 9 GB allocation on a 256 GB drive is normal and varies by Windows 11 version. You can monitor the reserved space through Settings > System > Storage > System & reserved. If you need to reclaim space temporarily, run Disk Cleanup with the Clean up system files option to remove old update caches. For advanced users who understand the risks, the registry method can disable Reserved Storage entirely, but this is not recommended for systems that rely on automatic updates. Keeping Reserved Storage enabled ensures that Windows 11 can install updates without requiring you to free up space manually.