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Your desktop background turned black after Windows 11 KB5120998

Last verified September 2026Tested against Windows 11 25H2 (OS Build 26200.9278), Windows 11 24H2 (OS Build 26100.9278), KB5120998 (27 August 2026, introduced the bug), KB5124008 (8 September 2026, contains the fix), Windows 11 25H2 (OS Build 26200.9445, fixed), Windows 11 24H2 (OS Build 26100.9445, fixed)Well documented

Microsoft fixed this on 8 September 2026. The September security update, KB5124008, addresses the bug that stopped desktop background and personalization settings from loading, and Microsoft has marked the known issue Resolved on both the 24H2 and 25H2 release-health pages. Install it from Settings > Windows Update, restart, and set your wallpaper again. Uninstalling KB5120998 was the only thing that worked for the first ten days, but it is no longer necessary - and if you already removed it, just take the September update.

Start here

  1. Check the build and rule out lookalikes
  2. Install the September 2026 security update (KB5124008)

For about ten days this bug had no vendor fix, and the advice everywhere - including on this page - was to remove the preview update that caused it. That changed on 8 September 2026. Microsoft's September security update names the fix explicitly: it "addresses an issue where desktop background and other personalization settings might not load correctly, causing the desktop background to appear black." The known issue moved to Resolved on the release-health pages for both Windows 11 24H2 and 25H2 the same day. So the shape of this problem has changed. If your wallpaper is black and you have not updated since August, you are three clicks from a real fix rather than a workaround. If you already uninstalled KB5120998 to get your wallpaper back, nothing is broken - installing the September update brings you back up to date and carries the fix with it. One honest caveat: KB5124008 shipped on 8 September and this page was re-checked on 9 September. Microsoft documents the fix in the KB article, but a day is not long enough for independent confirmation that it works on every affected machine. If it does not work on yours, the older workaround is still below.

Symptoms

  • The desktop background is a solid black colour instead of the wallpaper you set
  • Choosing a new wallpaper in Settings > Personalization > Background appears to work but reverts to black on sign-out or reboot
  • The slideshow no longer rotates, or contrast themes look wrong, following the same August 2026 update
  • The change first appeared after installing the 27 August 2026 optional preview update
  • Windows Update has not been run since before 8 September 2026, so the September security update is not installed yet
  • Microsoft Defender Antivirus, mouse cursor or Teams and Outlook on ARM problems arrived alongside it (all four are separate acknowledged bugs, not one)

Why this happens

On affected devices, KB5120998 stopped desktop settings loading at all

Microsoft's release-health entry, opened on 2 September 2026, says the issue is that some Windows Desktop settings fail to load, so the desktop background draws as the fallback solid black. On the same page Microsoft states that attempting to manually restore the customized settings does not work, because the issue prevents the correct loading of settings regardless of their value. Slideshow settings and contrast themes may be caught by the same failure. Microsoft never published the root cause, and unlike the sibling mouse-cursor bug it did not scope the wallpaper problem to non-English installations - the entry describes all affected devices on 25H2 and 24H2. Microsoft resolved it on 8 September 2026 with KB5124008.

Install the September 2026 security update (KB5124008)

It shipped alongside three unrelated bugs that people mistake for the same one

Four separate known issues surfaced within days of each other on 24H2 and 25H2: this wallpaper regression, a mouse cursor reset limited to non-English installations, a Microsoft Defender "antivirus is turned off" false notification, and a Teams/Outlook launch failure on ARM devices. They share a timeline and one of them (the cursor bug) came from the same KB5120998 update, so it is easy to mix them up. KB5124008 resolves three of the four; the Defender notification is a Defender-side bug and is still open. If Teams still will not launch or Defender still nags after the September update, treat those as their own problems - our sibling articles cover each one.

Check the build and rule out lookalikes

Fixes

Check the build and rule out lookalikes

about 3 min

This bug is bounded to specific Windows builds, and the build number also tells you whether the fix is already on the PC.

Applies to: Windows 11 24H2, Windows 11 25H2

  1. Press Windows key + R, type winver and press Enter.
    winver
  2. Read the OS Build line. Build 26200.9278 is Windows 11 25H2 with KB5120998 installed, and 26100.9278 is Windows 11 24H2 with KB5120998 installed. Those are the builds this bug affects.
  3. If you see build 26200.9445 or 26100.9445 or higher, KB5124008 is already installed and the fix for this bug is on the PC. A black desktop on those builds is something else - see "When something else is wrong" below.
  4. If you see a build lower than 26100.9278, KB5120998 is not on this PC, so this bug is not your problem either.
  5. If the mouse cursor also went back to the standard white pointer, or Microsoft Teams and Outlook are failing to launch on an ARM PC, those are separate acknowledged bugs from the same August-September 2026 window. KB5124008 fixes those too, but our sibling articles address each one individually.

Confirmed by the vendor.

Source: Microsoft, Microsoft, Microsoft, Microsoft

Install the September 2026 security update (KB5124008)

about 25 min

This is Microsoft's own fix. The KB article for KB5124008 states in as many words that it addresses desktop background and personalization settings failing to load, and Microsoft marked the known issue Resolved on the release-health pages for both 24H2 and 25H2 on the day it shipped.

Applies to: Windows 11 24H2, Windows 11 25H2

  1. Open Settings, then Windows Update, and click Check for updates.
  2. Install the September 2026 security update. On Windows 11 24H2 and 25H2 it is KB5124008, and it takes the build to 26100.9445 or 26200.9445 respectively. It is a security update, so it arrives through the normal channel - you do not need to look under Optional updates for it.
  3. Restart when prompted, then confirm the build with winver.
    winver
  4. Set your wallpaper again in Settings > Personalization > Background. The setting should now save and survive a sign-out and reboot.
  5. If updates are paused, clear the pause first in Settings > Windows Update, or the September update will not be offered. If you turned off "Get the latest updates as soon as they're available" while working around this bug, you can leave it off - that toggle only controls optional preview updates, not security updates.

Confirmed by the vendor.

Source: Microsoft, Microsoft, Microsoft

If you cannot take the September update yet, uninstall KB5120998

Check before applyingabout 20 min

This was the original workaround and it still works, but it is now the second choice. Use it only if something is holding the September security update back - a managed device, a deferral policy, or an update that will not install. Removing the preview update costs you no security fixes because it was never a security update.

Applies to: Windows 11 24H2, Windows 11 25H2

Before you do this

You also lose the preview features that shipped in KB5120998, including the taskbar, Start menu and Search improvements and the touchpad reliability fixes. This does not remove any security update. Prefer installing KB5124008 instead - it fixes the bug without giving anything up.

  1. Open Settings, go to Windows Update, then Update history.
  2. Scroll to the bottom and click Uninstall updates.
  3. Find KB5120998 in the list and click Uninstall. If it is not listed, it is not installed and this is a different problem.
  4. Restart the PC when prompted. Set your wallpaper again in Settings > Personalization > Background - it should now stick across sign-out and reboot.
  5. Come back to Windows Update once you are able to install KB5124008 or later. That is the real fix, and it also restores the preview features you lost by removing KB5120998.

Reported to work by 3 users; not confirmed by the vendor.

Source: Microsoft Community Hub, WinTips.org, WindowsLatest, Microsoft

Known issues

  • Microsoft's known issue "Desktop background settings are lost or reset on some devices" was opened on 2 September 2026 and marked Resolved on 8 September 2026 at 10:00 PT by KB5124008, on the release-health pages for both Windows 11 24H2 and 25H2. The KB5124008 article states the update addresses desktop background and other personalization settings not loading correctly. Microsoft never published a workaround of its own while the issue was open.

    Affects Windows 11 25H2 (26200.9278), Windows 11 24H2 (26100.9278) · Status: fixed

  • The two sibling bugs most often confused with this one are also fixed by KB5124008: the mouse customization reset on non-English installations, which came from the same KB5120998 preview update, and the Teams and new Outlook launch failure on ARM devices, which came from the August security update KB5121003. Both are marked Resolved by KB5124008 on the release-health pages as of 8 September 2026.

    Affects Windows 11 25H2, Windows 11 24H2, Windows 11 26H1 · Status: fixed

  • The Microsoft Defender "antivirus is turned off" false notification is a separate problem and was never fixed by KB5124008 — it is triggered by Defender's own definition updates rather than by a Windows cumulative update. Microsoft moved it to Resolved on 17 September 2026, in Microsoft Defender Antivirus platform version 4.18.26080.4. If you are seeing that notification as well, let Defender update itself rather than looking for a Windows patch.

    Affects Windows 11 26H1, Windows 11 25H2, Windows 11 24H2, Windows 11 23H2, Windows 10 22H2 · Status: fixed

If none of this worked

If winver shows build 26200.9445 or 26100.9445 or higher, KB5124008 is installed and the bug described here is fixed on your PC. A black desktop on those builds has a different cause, and so does a black desktop that predates 27 August 2026. A missing wallpaper file or unavailable network share will render as black - Windows cannot draw an image it cannot read. Themes stored in OneDrive that has fallen out of sync do the same. Some enterprise Group Policies enforce a solid colour or block wallpapers on unactivated Windows installations, so check that Windows is activated in Settings > System > Activation. Third-party wallpaper tools (Lively, Wallpaper Engine) can also leave the desktop blank when the tool crashes or the video-playback service is not running. If you are on the fixed build and the wallpaper still will not stick, the useful next step is to sign in to a freshly created local user account and set a wallpaper there. If it works in the new account, the problem is in your user profile rather than in Windows, and no update will fix it.

Common questions

Has Microsoft fixed it?
Yes. KB5124008, the September 2026 security update released on 8 September, states that it addresses desktop background and other personalization settings failing to load and causing a black background. Microsoft marked the known issue Resolved on both the Windows 11 24H2 and 25H2 release-health pages the same day. Install the update and restart. Note that this page was re-checked on 9 September, one day after the fix shipped, so there has not yet been time for independent confirmation across a wide range of machines.
I already uninstalled KB5120998. What should I do now?
Nothing urgent, and nothing is broken. Run Windows Update and install KB5124008. That brings you back up to date, carries the fix for this bug, and restores the taskbar, Start menu and Search improvements you gave up when you removed the preview update. If you also turned off "Get the latest updates as soon as they're available", you can leave that off - it only controls optional preview updates.
Do I still need to uninstall KB5120998?
No. Installing KB5124008 is the better move in every case: it fixes the bug and you keep the preview features. Uninstalling is now only worth doing if something is genuinely blocking the September update, such as a work-managed PC with deferral policies, or an update that will not install.
Is it safe to uninstall KB5120998?
Yes, if you need to. It is an optional preview update delivered through Optional updates rather than the security channel, so removing it leaves your PC at the same patch level for security. You do lose the preview features it added - the taskbar and Start menu improvements, File Explorer performance work, Windows Search tweaks and the touchpad reliability fixes.
Is this the same bug as the mouse cursor reset?
No, they are different code paths, though they arrived in the same update and are now fixed by the same one. The cursor reset is a separate known issue that Microsoft scoped to non-English Windows installations only. The desktop background bug has no language qualifier on Microsoft's page - it is described as affecting all impacted 25H2 and 24H2 devices. KB5124008 resolves both.
What about slideshow, contrast themes and other personalization settings?
Microsoft's release-health entry says those may be affected as well - the failure is in the code that loads desktop settings, so anything driven from Personalization can miss. The KB5124008 description covers "desktop background and other personalization settings", so the same update should restore them. If your slideshow no longer rotates or your contrast theme looks wrong at the same time as the black wallpaper, install the update and re-apply the setting.

Did this fix work?

If a step is wrong, outdated, or did not help, telling us is the fastest way to get it corrected. Reports are reviewed before new articles.

Report a problem with this page

Related problems

Sources

  • Windows 11, version 25H2 known issues and notificationsOfficial

    Microsoft · Support page · checked Sep 21, 2026

    • Microsoft marked the known issue "Desktop background settings are lost or reset on some devices" Resolved by KB5124008 on 8 September 2026 at 10:00 PT
    • The issue was opened on 2 September 2026 and affects Windows 11 version 25H2 and version 24H2, client only
    • Microsoft states the desktop background draws as a solid black because settings fail to load, and that manually restoring the settings does not work
    • Slideshow settings and contrast themes may be affected by the same failure
  • Windows 11, version 24H2 known issues and notificationsOfficial

    Microsoft · Support page · checked Sep 21, 2026

    • The same desktop background known issue is listed as Resolved by KB5124008 on the Windows 11 24H2 release-health page, last updated 8 September 2026 10:41 PT
    • The mouse customization reset from KB5120998 is also marked Resolved by KB5124008
    • The Teams and Outlook launch failure on ARM devices from KB5121003 is marked Resolved by KB5124008
    • The incorrect "Microsoft Defender Antivirus is turned off" notification was moved to Resolved on 17 September 2026, fixed in Microsoft Defender Antivirus platform version 4.18.26080.4 rather than by any Windows update
  • September 8, 2026 - KB5124008 (OS Builds 26100.9445 and 26200.9445)Official

    Microsoft · Release notes · checked Sep 21, 2026

    • KB5124008 was released on 8 September 2026 and produces OS Builds 26100.9445 and 26200.9445
    • Microsoft states the update "addresses an issue where desktop background and other personalization settings might not load correctly, causing the desktop background to appear black"
    • The same update addresses customized mouse cursor settings not displaying correctly, and Teams and Outlook closing unexpectedly on Arm64 PCs
    • Microsoft states it is not currently aware of any issues with KB5124008
  • August 27, 2026 - KB5120998 (OS Builds 26100.9278 and 26200.9278) PreviewOfficial

    Microsoft · Release notes · checked Sep 21, 2026

    • KB5120998 is the optional preview update of 27 August 2026 producing OS Builds 26100.9278 and 26200.9278
    • It is delivered through Optional updates rather than the security channel
    • Re-checked on 21 September 2026: Microsoft has since added a Known issues section to this page listing the desktop background reset, the mouse customization reset on non-English installations and the Arm64 Teams and Outlook failure, each shown as addressed by the 8 September 2026 update.
  • Windows 11 KB5120998 Breaks Mouse Cursor and Wallpaper Personalization (FIX)Reputable

    WinTips.org · News · checked Sep 21, 2026

    • Independent write-up of the KB5120998 wallpaper and cursor regressions reporting that removing the update restores both
    • Updated on 9 September 2026 to lead with Microsoft's fix, stating that KB5124008 resolves the KB5120998 desktop background and personalization issue; it still documents removing KB5120998 as the earlier workaround.
  • Skip today's Windows 11 update: it breaks cursor styling, resets wallpaper, and moreReputable

    WindowsLatest · News · checked Sep 21, 2026

    • Contemporaneous reporting on 28 August 2026 that KB5120998 reset wallpaper and cursor personalization for affected users
    • KB5120998 is an optional preview update that a user has to choose to install
  • Desktop background blackCommunity report

    Microsoft Community Hub · Forum · checked Sep 21, 2026

    • Multiple users independently reported the desktop background turning solid black after KB5120998 and reverting on reboot
    • Users reported that uninstalling KB5120998 restored the wallpaper
KB5120998 black wallpaper: fixed by KB5124008 | TroubleGrid