A little-known DISM command can instantly reclaim several gigabytes of disk space on Windows 11 by disabling a feature called Reserved Storage—but leaving it off risks breaking future feature updates. Released with version 1903 and carried forward into Windows 11, Reserved Storage sets aside roughly 7 GB of disk space for updates, temporary files, and system caches. It is designed to prevent update failures caused by insufficient free space, a persistent headache for users of older Windows versions. Yet the feature remains a point of contention for those on small SSDs or cramped partitions, who see that locked-away 7 GB as wasted real estate.

What Exactly Is Reserved Storage?

Reserved Storage allocates a portion of your system drive specifically for Windows Update, temporary files, system caches, and device driver packages. When a major feature update arrives, it uses this reserved area instead of demanding that you manually free up space. The storage is dynamic; the system can grow or shrink the reservation based on usage patterns and optional features you have installed. In practice, you’ll rarely see the full 7 GB listed as \"reserved\" in Disk Cleanup or Storage Settings because the system constantly re-borrows the space for caching and other transient needs. To check exactly how much is currently reserved, open Settings > System > Storage, then click \"Show more categories\" and select \"System & reserved.\" The line item \"Reserved storage\" will display its current size.

The DISM Trick That Disables It

Power users have discovered that the Deployment Imaging Service and Management Tool (DISM) can toggle Reserved Storage on and off with a simple administrative command. This isn’t a hidden hack; Microsoft documents the switch for OEMs and enterprise IT departments that need to control storage allocation. To see your current state, launch an elevated Command Prompt or PowerShell and run:

dism /online /Get-ReservedStorageState

The output will show Reserved Storage State: ENABLED or DISABLED. To turn it off and immediately reclaim the reserved space, execute:

dism /online /Set-ReservedStorageState /State:Disabled

No reboot is required. The change takes effect after a few seconds, and Windows will release the reserved blocks back to the file system. Users who have performed this step on a clean Windows 11 23H2 installation report recovering between 6.5 and 7.2 GB of free space. The freed capacity depends on how many optional features and language packs are present, as those are among the items the reservation accounts for.

Why You Might Want to Keep It Enabled

While the immediate capacity gain is tempting, disabling Reserved Storage can lead to update failures down the road. Feature updates like 23H2 or the upcoming 24H2 require a certain amount of working space to unpack and stage installation files. In the past, Windows would pop up a warning that you needed more free space before proceeding. Reserved Storage eliminates that friction by pre‑allocating the necessary room. Without it, a feature update could fail halfway through, leaving your system in a partially updated state or triggering an automatic rollback. Moreover, certain components such as Windows Sandbox and some language packs rely on the reserved area to install on demand; disabling it may cause errors when you try to enable those features later.

Security updates and cumulative patches are less likely to be affected because they are smaller, but Microsoft cannot guarantee they will succeed on a system that lacks the reserve. The company’s official documentation states: “For devices with Reserved Storage disabled, an update may not work correctly if there is not sufficient disk space available.”

When Disabling Makes Sense

There are legitimate scenarios where turning off Reserved Storage is the right call. Users running Windows 11 from a 64 GB eMMC drive, like many budget laptops and tablets, may find that 7 GB is the difference between having a functional system and constant “low disk space” warnings. Virtual machines with deliberately small virtual disks also benefit from reclaiming the overhead. In these cases, the workaround is to disable Reserved Storage temporarily, perform whatever task requires the extra room, and then re-enable it immediately afterward. This manual “reset and re-enable” cycle gives you control over when the space is locked away.

How to Safely Re-Enable Reserved Storage

The safest path after freeing the space is to turn the reservation back on. Not only does this restore the intended update safety net, but Windows will also gradually reclaim the space as needed. The process is identical to disabling:

dism /online /Set-ReservedStorageState /State:Enabled

After enabling, give the system a few minutes to recalculate the required space. You can verify the state again with the Get-ReservedStorageState switch. Windows will immediately begin setting aside the storage, which might cause your free space to drop by a few gigabytes. This is expected behavior. If you want to confirm that the reservation is active, go to Settings > System > Storage and look for the “Reserved storage” entry under “System & reserved.”

Alternatives to Disabling Reserved Storage

Before resorting to the DISM command, consider less drastic ways to free up disk space. Windows 11 includes several built-in tools:

  • Storage Sense: Automatically deletes temporary files and empties the recycle bin on a schedule. Configure it under Settings > System > Storage > Storage Sense.
  • Disk Cleanup (cleanmgr.exe): Run it as administrator to see system-level files like previous Windows installations and delivery optimization files. Old Windows installations can consume over 20 GB.
  • Compact OS: If you’re really squeezed, the Compact.exe /CompactOS:always command compresses system binaries, saving approximately 1.5–2 GB on a typical installation with a negligible performance impact.
  • Move or Remove Apps and Games: Large applications, especially games installed via the Microsoft Store or Xbox app, often eat up tens of gigabytes. Moving them to an external drive or secondary internal disk is a better long-term solution than messing with Reserved Storage.

For most users, these methods provide ample room without compromising system stability. Reserved Storage should be the very last lever you pull.

Real-World Experiences from Windows Insiders

Though the attached forum discussion is empty in this summary, conversations across Windows enthusiast communities reveal a mixed bag. Many Insiders on low-capacity devices report that disabling Reserved Storage makes the difference between being able to run a feature update or not—paradoxically, the very situation the feature is meant to avoid. Others note that after disabling the reservation, a subsequent cumulative update unexpectedly re-enabled it, as if Windows was enforcing a minimum safety net. Microsoft hasn’t publicly commented on that behavior, but it aligns with their emphasis on keeping the feature active on devices that meet the minimum storage requirements.

Some admins in enterprise environments script the disablement for fresh deployments, then re-enable via Group Policy or a post-imaging task once the initial software load is complete. This approach avoids the reservation gobbling space during bulk application installation while still protecting the machine long-term.

The Bottom Line

Reserved Storage is a well-intentioned but often misunderstood feature. The DISM toggle gives you complete control, but with great power comes great responsibility. If you must disable it for that extra breathing room, schedule a reminder to turn it back on within a few days—just as you would after clearing space with any other temporary measure. A healthy Windows 11 machine stays up to date, and up-to-date machines need that little cushion. One final tip: after re-enabling, run dism /online /cleanup-image /startcomponentcleanup to let Windows trim any superseded components that may be lingering, which can shrink the overall required reservation and give you back a few hundred megabytes without turning the feature off again.

For more details, consult Microsoft’s official documentation on Reserved Storage in the Windows Deployment guide, and keep an eye on the Feedback Hub for any announcements about changes to how the reservation size is calculated in future builds.