Windows 10 reserved storage explained

Martin Brinkmann
Jan 8, 2019
Updated • Jan 8, 2019
Windows, Windows 10

Microsoft revealed today that it plans to integrate a feature called reserved storage in Windows 10 version 1903, the next feature update of the operating system.

Windows 10 will set aside some available storage automatically so that it is  used exclusively by the operating system.

Through reserved storage, some disk space will be set aside to be used by updates, apps, temporary files, and system caches.

Microsoft wants to improve the reliability of "critical OS functions" that rely on disk space, e.g. updating or caching, by reserving disk space.

Existing devices won't have the reserved storage functionality enabled by default; new Windows 10 version 1903 installations and systems that come pre-installed with that particular version of Windows 10 -- and future versions -- will make use of reserved storage automatically.

windows 10 reserved storage

Microsoft notes that reserved storage will set aside about 7 Gigabytes of space; not a lot if Windows is installed on a device with lots of free storage but quite a lot if it is on a device with 16 or 32 Gigabytes of storage space.

The 7 Gigabytes that Windows 10 will reserve initially may change over time, and Windows 10 may use other space if the reserved storage is out of space.

The size depends on two major factors -- optional features and installed languages -- which are used to determine the reserved space.

Windows 10 users can check the size of reserved storage by going to Settings > System > Storage > Show more categories > System & Reserved. There you find listed the reserved storage that Windows 10 has set aside.

Administrators may reduce the size of reserved storage by removing optional features or languages, if installed. Reserved Storage may increase if additional features or languages are installed on a device.

It is not possible, however,  to remove reserved storage from the operating system. It is unclear if that means that reserved storage cannot be disabled anymore once activated, or if that just means that data that is stored in the reserved storage area cannot be removed by users.

Windows 10 will delete files in reserved storage regularly when they are not needed anymore

Microsoft published the following instructions to enable Reserved Storage on Windows 10 Insider Builds:

  1. Right-click the Windows icon on the taskbar, search for Registry Editor, and Open it.
  2. If prompted, select Yes to allow the app to make changes to your device.
  3. Select HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ReserveManager.
  4. Right click ShippedWithReserves to modify and update the value to “1.”
  5. After you upgrade the device to the next available build, you will be using reserved storage!

A value of 1 means that Reserved Storage space is enabled, a value of 0 that it is not enabled.

It remains to be seen if it is possible to set the value to 0 on devices that come with Reserved Storage enabled to disable the feature and free up space.

How does it work?

Microsoft's explanation on Technet falls a bit short as it is not clear just from reading the article how Windows 10 reserves the storage space. Craig Barkhouse explains in a comment that Microsoft created a solution that adds "new support" for that to the NTFS file system.

The idea is NTFS provides a mechanism for the servicing stack to specify how much space it needs reserved, say 7GB. Then NTFS reserves that 7GB for servicing usage only.

Barkhouse notes that the main drive will report the available space and that the reserved storage is subtracted automatically from that.

Closing Words

The use of reserved storage should improve the reliability and stability of certain processes, e.g. updating; that is a good thing but the whole feature may make low storage devices running Windows 10 even less appealing than they are already.

Now You: What is your take on Reserved Storage?

Windows 10 reserved storage explained
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Windows 10 reserved storage explained
Microsoft revealed today that it plans to integrate a feature called reserved storage in Windows 10 version 1903, the next feature update of the operating system.
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  1. Dan Donx said on January 15, 2023 at 10:29 am

    What mental age of reader are you targeting with the first sentence? 10?

    Why not write an article on how to *avoid* upgrading from W10 to W11. Analogous to those like me who avoided upgrading from 7 to 10 for as long as possible.

    If your paymaster Microsoft permits it, of course.

  2. Dexter said on January 15, 2023 at 11:14 am

    5. Rufus
    6. Ventoy

    PS. I hate reading these “SEO optimized” articles.

    1. cdr said on January 15, 2023 at 3:32 pm

      I used Rufus to create an installer for a 6th gen intel i5 that had MBR. It upgraded using Setup. No issues except for Win 11 always prompting me to replace my local account. Still using Win 10 Pro on all my other PCs to avoid the bullying.

  3. sv said on January 15, 2023 at 6:40 pm

    bit pointless to upgrade for the sake of upgrading as you never know when you’ll get locked out because ms might suddenly not provide updates to unsupported systems.

    ps…. time travelling?
    written. Jan 15, 2023
    Updated • Jan 13, 2023

    1. Martin Brinkmann said on January 16, 2023 at 5:49 am

      This happens when you schedule a post in WordPress and update it before setting the publication date.

  4. Anonymous said on January 16, 2023 at 8:24 am

    Anyone willing to downgrade to this awful OS must like inflicting themselves with harm.

  5. basingstoke said on January 16, 2023 at 11:18 am

    I have become convinced now that anybody who has no qualms with using Windows 11/10 must fit into one of the following brackets:

    1) Too young to remember a time before W10 and W11 (doesn’t know better)

    2) Wants to play the latest games on their PC above anything else (or deeply needs some software which already dropped W7 support)

    3) Doesn’t know too much about how computers work, worried that they’d be absolutely lost and in trouble without the “”latest security””

    4) Microsoft apologist that tries to justify that the latest “features” and “changes” are actually a good thing, that improve Windows

    5) Uses their computer to do a bare minimum of like 3 different things, browse web, check emails, etc, so really doesn’t fuss

    Obviously that doesn’t cover everyone, there’s also the category that:

    6) Actually liked W7 more than 10, and held out as long as possible before switching, begrudgingly uses 10 now

    Have I missed any group off this list?

    1. Heinz Strunk said on September 19, 2023 at 3:57 pm

      You have missed in this group just about any professional user that uses business software like CAD programs or ERP Programs which are 99% of all professional users from this list.

      Linux doesn’t help anyone who is not a linux kid and apple is just a fancy facebook machine.

  6. ilev said on August 24, 2023 at 7:34 pm

    Microsoft has removed KB5029351 update

    1. EP said on August 24, 2023 at 9:21 pm

      only from windows update though
      KB5029351 is still available from the ms update catalog site

  7. Anonymous said on August 24, 2023 at 11:05 pm

    1. This update is labaled as PREVIEW if it causes issues to unintelligent people, then they shouldn’t have allowed Preview updates ot install.

    2. I have installed it in a 11 years old computer, and no problems at all.

    3. Making a big drama over a bluescreen for an updated labeled as preview is ridiculous.

    This is probably another BS internet drama where people ran programs and scripts that modified the registry until they broke Windows, just for removing stuff that they weren’t even using just for the sake of it.
    Maybe people should stop playing geeks and actually either use Windows 10 or Windows 11, but don’t try to modify things just for the sake of it.

    Sometimes removing or stopping things (like defender is a perfect example) only need intelligence, not scripts or 3rd party programs that might mess with windows.

  8. john said on August 24, 2023 at 11:17 pm

    Windows 11 was a pointless release, it was just created because some of the Windows team wanted to boost sales with some sort of new and improved Windows 10. Instead, Microsoft cannot support one version well let alone two.

    1. John G. said on August 25, 2023 at 12:08 pm

      Windows 11 is the worst ugly shame by Microsoft ever. They should release with every new W11 version a complete free version of Starallback inside just to make this sh** OS functionally again.

  9. EP said on August 25, 2023 at 3:10 pm

    motherboard maker MSI has recently released a statement regarding the “unsupported processor” blue screen error for their boards using Intel 600/700 series chipsets & to avoid the KB5029351 Win11 update:–UNSUPPORTED-PROCESSOR–Error-Message-of-Windows-11-Update-KB5029351-Preview-142215

  10. EP said on August 29, 2023 at 7:32 pm

    check out the following recent articles:

    Neowin – Microsoft puts little blame on its Windows update after UNSUPPORTED PROCESSOR BSOD bug:

    BleepingComputer – Microsoft blames ‘unsupported processor’ blue screens on OEM vendors:

  11. Leonard Britvolli said on August 30, 2023 at 10:33 pm

    While there may be changes or updates to the Windows 10 Store for Business and Education in the future, it is premature to conclude that it will be discontinued based solely on rumors.

  12. sembrador said on September 5, 2023 at 9:32 pm

    My advice, I left win 15 years ago. Now I’m a happy linux user (linuxmint) but there is Centos, Fedora, Ubuntu depending on your needs.

  13. EP said on September 6, 2023 at 11:55 am

    motherboard maker MSI has recently released new BIOS/firmware updates for their Intel 600 & 700 series motherboards to fix the “UNSUPPORTED_PROCESSOR” problem (Sept. 6):–UNSUPPORTED-PROCESSOR–caused-BSOD-on-MSI-s-Intel-700-and-600-Series-Motherboards-142277

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