You install the latest optional update.
You restart your PC.
And then — your mouse cursor is gone.
Or it's huge. Or it's a giant white arrow that looks like it's from Windows 98.
Your wallpaper is black. Your custom cursor settings are gone.
You try to fix it. You restart again. It happens again.
You might think:
"Is my PC broken? Do I need to reinstall Windows?"
No.
On August 30, 2026, Microsoft officially confirmed that the optional update KB5120998 (released on August 27) is causing these exact issues.
The good news? This update is optional — and you can safely uninstall it.
This guide shows you exactly how to fix the KB5120998 mouse cursor and wallpaper problems — step by step.
What Microsoft Confirmed About KB5120998
Microsoft has officially acknowledged the following issues with the KB5120998 optional update:
| Issue | Description |
|---|---|
| Cursor disappears | The mouse pointer is completely invisible |
| Cursor size changes | The cursor becomes very large or very small |
| Cursor resets | Custom cursor schemes revert to default |
| White cursor | The cursor turns into a large white pointer |
| Wallpaper turns black | Desktop background changes to solid black |
| Settings don't stick | Even if you fix them, the issues return after restart |
Microsoft's official guidance: Users experiencing these issues should uninstall KB5120998. The problem is being investigated, and a permanent fix is expected in a future update.
How to Fix the KB5120998 Mouse and Wallpaper Issues
Fix 1: Uninstall KB5120998 (Recommended — The Most Reliable Fix)
Since Microsoft has confirmed the issue, uninstalling the update is the most reliable solution.
Important: KB5120998 is an optional preview update. Uninstalling it removes that optional update; it does not require reinstalling Windows.
How to uninstall from Settings:
- Open Settings → Windows Update → Update history
- Scroll down and click Uninstall updates
- Find KB5120998 in the list
- Click Uninstall
- Follow the prompts and restart your PC
How to uninstall from WinRE (if your PC won't boot normally):
- Boot into Windows Recovery Environment (WinRE)
- Go to Troubleshoot → Advanced options → Uninstall Updates
- Select Uninstall latest quality update
- Follow the prompts
- Restart your PC
After uninstalling: Check whether your cursor and wallpaper have returned to normal.
Fix 2: Restore Your Cursor Settings (If You Want to Keep the Update)
If you absolutely need to keep KB5120998 installed, you can try restoring your cursor settings manually. However, if the underlying update issue remains, the settings may revert after a restart.
How to restore cursor settings:
- Open Settings → Personalization → Themes
- Click Mouse cursor
- Under Scheme, select your preferred cursor scheme
- Click Apply → OK
Alternative (via Control Panel):
- Open Control Panel → Mouse
- Go to the Pointers tab
- Select your preferred scheme from the dropdown
- Click Apply → OK
Note: This is a workaround rather than a guaranteed permanent fix.
Fix 3: Restore Your Wallpaper
If your wallpaper turned black during the update, you can change it back.
How to change your wallpaper:
- Right-click on the desktop → Personalize
- Click Background
- Select a new background image or color
- Click Apply
Note: If the update is still installed, the wallpaper problem may return.
Fix 4: Pause Windows Updates Temporarily
After uninstalling the update, you can temporarily pause Windows Update while waiting for Microsoft's next update or a confirmed fix.
How to pause updates:
- Open Settings → Windows Update
- Click Pause updates
- Select the available pause period
Note: Pause updates only temporarily. Windows will resume updates automatically after the selected period.
What NOT to Do
- Don't reinstall Windows — this issue is associated with the optional update.
- Don't change random registry settings — there's no need for registry modifications as a first-line fix.
- Don't repeatedly reset your cursor settings — if the update is causing the problem, the settings may revert.
- Don't panic — removing the problematic optional update is much simpler than reinstalling the entire operating system.
How SysPulse Can Help You Monitor System Changes
Problems like unexpected Windows updates can be frustrating.
If you want to know when something changes on your PC, automatic monitoring can help.
That's why I built SysPulse — a lightweight Windows security and monitoring tool.
SysPulse can:
- Detect new processes and show their full file paths
- Monitor CPU and RAM anomalies
- Detect USB connections in real-time
- Detect startup changes
- Send Telegram alerts for monitored events
- Use less than 30MB of RAM
You can set it up and let it monitor your PC in the background — so you know when something changes, even if you're not at your desk.
You can find it at: syspulse.pro
Summary Table
| Problem | Quick Fix |
|---|---|
| Cursor disappeared or changed size | Uninstall KB5120998 |
| Wallpaper turned black | Uninstall KB5120998 |
| Cursor settings keep resetting | Uninstall KB5120998 |
| Want to avoid the issue temporarily | Pause Windows Updates |
| Want to monitor system changes | Use SysPulse |
Final Thought
The KB5120998 issue can be frustrating, especially when your cursor suddenly disappears or your wallpaper turns black.
Start with the simplest solution:
- Check whether KB5120998 is installed
- Uninstall it if you're experiencing the reported problems
- Restart your PC
- Pause updates temporarily if necessary
The key: Don't panic. A problematic optional update doesn't mean your PC is broken.
And if you want to stay informed about important changes happening on your system, consider a lightweight monitoring tool that alerts you in real-time.
Have questions about fixing the KB5120998 issues? Drop a comment below — I read every one.
Stay secure!
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