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Severe System Lag & DISM Error 0x800f0915 after 2026-05 Updates (Build 26200.8037)

Stella 25 Reputation points
2026-05-27T13:55:32.3533333+00:00

Hello everyone,

I am experiencing severe system performance degradation, frequent File Explorer freezes, and a persistent DISM error on my Windows 11 Insider Preview build. I would appreciate some expert guidance on how to safely resolve this.

System Specifications

Current OS Build: Windows 11 Insider Preview, Build 26200.8037

Experience Pack: Windows Feature Experience Pack 1000.26100.300.0

DISM Tool Version: 10.0.26100.5074

Image Version: 10.0.26200.8037

The Chronology of the Issue

The Triggering Updates:

My system automatically installed two updates recently:

2026-05 Security Update (KB5089549) (which bumped the system to 26200.8457)

2026-05 .NET Framework Security Update (KB5087051)

Symptoms:

Immediately after these updates, my File Explorer frequently showed "Not Responding" and took an incredibly long time to load directories (especially those containing large data/project files). All other applications became extremely sluggish to launch, and running heavy programs like codex caused frequent crashes.

Current State & Detailed Command Outputs:

I successfully uninstalled both KB5089549 and KB5087051, which reverted my system build back to 26200.8037. However, the severe system lag and File Explorer unresponsiveness persist.

To diagnose the issue, I ran SFC and DISM tools in an elevated Command Prompt. Here are the exact results:

sfc /scannow

Output: Windows Resource Protection did not find any integrity violations.

Dism /Online /Cleanup-Image /CheckHealth

Output: No component store corruption detected. The operation completed successfully.

Dism /Online /Cleanup-Image /ScanHealth

Output: [==========================100.0%==========================] The component store is repairable. The operation completed successfully.

Dism /Online /Cleanup-Image /RestoreHealth

Output:

[==========================100.0%==========================]

Error: 0x800f0915

The repair content could not be found anywhere. Check the internet connectivity or use the "Source" option to specify the location of the files that are required to restore the image.

My Questions

Since /ScanHealth explicitly states "The component store is repairable", but /RestoreHealth consistently fails with Error 0x800f0915 due to missing online sources, how can I successfully force the repair? (Note: My DISM tool version 26100 is older than the actual system image version 26200).

What is the best way to completely fix this severe performance degradation and the 0x800f0915 error without losing my personal files, installed apps, and research data?

If anyone can provide advanced command workarounds, update component reset scripts, or advice on performing an In-Place Upgrade for this specific preview branch, it would be highly appreciated.

Thank you in advance for your time and assistance!

Windows Insider program | Windows Insider preview | Install, activate, and Windows update

Answer accepted by question author

Hendrix-V 15,345 Reputation points Microsoft External Staff Moderator
2026-05-28T06:11:57.54+00:00

Hi Stella,

Thanks for providing such detailed troubleshooting results, that makes it much easier to pinpoint what’s going on.

Your logs show a specific pattern:

  • The system detects that the component store can be repaired
  • But DISM fails with 0x800f0915 (“repair content not found”)

This usually means the repair process cannot access matching source files for your current build, often due to version mismatch or a partially inconsistent update state after recent patches. Because of this, the underlying corruption remains, which can explain the persistent lag and Explorer freezes even after uninstalling updates.

At this point, here are some possible troubleshooting steps that you can try:

1, Repair using a matching Windows ISO - use a local source that matches your installed build to complete the repair:

  • Download a Windows 11 ISO (same or closest build to yours)
  • Mount the ISO then run: DISM /Online /Cleanup-Image /RestoreHealth /Source:X:\sources\install.wim /LimitAccess (Replace X: with the mounted ISO drive)

2, If DISM still fails > perform an in-place repair

  • Mount the same ISO
  • Run setup.exe
  • Choose Keep personal files and apps

Let me know if you need any further help. Feel free to ask by clicking "Add Comment" or "Add Reply" if you are unable to add a comment, so that your reply is visible. I appreciate your effort.

Note: Follow the instructions in our documentation to enable email notifications if you wish to receive notifications about this conversation.

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  1. AI answer

    2026-05-27T13:56:19.34+00:00

    The component store is likely corrupted or missing repair sources, which causes DISM to fail with 0x800f0915. The DISM tool version difference itself isn’t the key issue; DISM can repair the online image as long as it can reach valid sources (Windows Update or a matching Windows image). When those sources are unavailable or damaged, 0x800f0915 occurs.

    Use the following sequence to repair the system while preserving files and apps.

    1. Run DISM with an explicit repair source

    If the device can’t pull files from Windows Update, specify a known-good Windows installation or image as the source.

    1. Open an elevated Command Prompt (Run as administrator).
    2. Connect to a working Windows installation or mounted image that matches the same OS version/branch.
    3. Run DISM with a source and limit access to Windows Update, for example:
    DISM.exe /Online /Cleanup-Image /RestoreHealth /Source:\\<servername>\c$\windows /LimitAccess

    Replace <servername> with the computer name or path of the repair source. The repair source must be running the same OS version. This forces DISM to use that source instead of Windows Update and can clear 0x800f0915 when the online component store is missing content.

    If DISM completes with “The restore operation completed successfully”, proceed to System File Checker.

    1. Run System File Checker (SFC)

    After DISM succeeds, verify and repair protected system files:

    1. In the same elevated Command Prompt, run:
    sfc /scannow
    1. Wait for the verification to reach 100% and review the result:
      • If “Windows Resource Protection found corrupt files and successfully repaired them”, restart and test performance.
      • If SFC reports it found corrupt files but couldn’t fix some, use the SFC log to identify and manually replace problem files as described in the System File Checker documentation.
    2. Repair Windows Update corruption and caches

    Because the issue started after updates and persists after uninstalling them, clean up Windows Update components and caches.

    1. Open an elevated Command Prompt.
    2. Stop update services and rename SoftwareDistribution and Catroot2:
    net stop bits
net stop wuauserv
ren %systemroot%\softwaredistribution softwaredistribution.bak
ren %systemroot%\system32\catroot2 catroot2.bak
net start bits
net start wuauserv
    1. Restart the device and run Windows Update again to rebuild the update cache.

    If update-related corruption was contributing to DISM failures or performance issues, this reset plus the DISM/SFC sequence can stabilize the system.

    1. Check and repair disk errors

    Underlying disk issues can cause both lag and corruption in system files.

    1. Open an elevated Command Prompt.
    2. Run:
    chkdsk /f C:
    1. Approve the scan at next restart if prompted, then restart and let the scan complete.
    2. If DISM still fails or performance remains poor: perform an in-place repair install

    If DISM with a proper source and SFC cannot fully repair the image, or if lag and Explorer freezes persist, perform an in-place repair install (repair upgrade) of the same Windows branch. This keeps personal files and apps while replacing system components.

    From the provided guidance on similar update failures:

    • Use the in-place upgrade/repair install option from Settings → System → Recovery → Reinstall (or equivalent for the Insider branch), choosing to keep personal files and apps.
    • Alternatively, mount a matching ISO for the current Insider build and run Setup, selecting the option to keep personal files and apps.

    This approach has been recommended for Insider and preview build update errors (for example, 0x800f081f and other update failures) and is effective when the component store is too damaged for DISM to repair.

    1. Last resort if preview build remains unstable

    If even a repair install does not stabilize the Insider build, the supported recovery pattern for persistent preview build issues is:

    • Pause Insider updates and wait for a newer build that may fix the regression, or
    • Back up important files and perform a clean install of a stable build, then rejoin the Insider channel if needed.

    However, this is only after attempting DISM with a valid source, SFC, update cache reset, disk check, and an in-place repair install.

    Summary of recommended order

    1. Run DISM /Online /Cleanup-Image /RestoreHealth with a valid /Source and /LimitAccess.
    2. Run sfc /scannow and ensure system files are repaired.
    3. Reset Windows Update components (BITS/WUAUSERV, SoftwareDistribution, Catroot2).
    4. Run chkdsk /f C: to repair disk-level issues.
    5. If issues persist, perform an in-place repair install of the same Insider build while keeping files and apps.

    These steps address both the DISM 0x800f0915 error (by providing a valid repair source and cleaning the component store) and the underlying system corruption that can cause severe lag and Explorer freezes, without wiping personal data or installed applications.

    References:

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  2. CrazyKats 15,775 Reputation points Volunteer Moderator
    2026-05-29T00:04:41.46+00:00

    Hi Star,

    Please also make sure that your build is up

    to date. You seem to be behind.

    This build is up to 26200.8524.

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