The red corner flash is not an officially listed Windows 11 25H2 issue, so first isolate software that briefly starts screen capture, recording, sharing, or an overlay.
Windows’ capture APIs display a colored border around a window or display while capture is active, unless the capturing app has permission to suppress it.^1^ A border that appears only momentarily can therefore indicate that an application is creating and immediately ending a capture session. However, the evidence does not identify which application—or conclusively establish that capture is the cause.
Isolate a capture or overlay application
- Open Task Manager with Ctrl+Shift+Esc.
- Select Startup apps.
- Temporarily disable nonessential applications associated with:
- screen recording or screenshots;
- meeting and remote-support software;
- game overlays;
- GPU utilities;
- Lenovo display, camera, presence-sensing, or collaboration features.
- Restart the laptop and test normal app/tab switching.
- Re-enable the items individually until the flash returns.
Also check the notification area and each relevant desktop application’s own settings for recording, instant replay, screen sharing, overlay, or capture features. Desktop applications are not necessarily controlled by Windows’ per-app background setting and may need to be disabled through their own settings.^2^
If selective startup-app testing does not identify it, perform a clean boot:
- Search for msconfig and open System Configuration.
- On Services, select Hide all Microsoft services, then Disable all.
- Select Startup → Open Task Manager and disable enabled startup items.
- Restart and test.
- If the flash disappears, re-enable half the disabled items at a time, restarting between tests, until the responsible program is isolated.
A clean boot starts Windows with essential drivers and startup programs and is intended to identify background software conflicts.^3^ Keep a record of disabled items so normal startup can be restored afterward.
Distinguish an app artifact from a display-driver artifact
Leave Task Manager visible while reproducing the flash:
- Task Manager flashes too: investigate the display driver.
- Task Manager remains stable while another area flashes: an incompatible or background application is more likely.
Microsoft uses this test to separate display-driver problems from application-related flicker.^4^
For a likely driver issue:
- Press Windows+Ctrl+Shift+B once to reset the graphics driver.
- If the symptom continues, open Device Manager → Display adapters.
- Open the adapter’s Properties → Driver:
- Use Roll Back Driver if the symptom began immediately after a driver update.
- Otherwise, install the Yoga 9 graphics driver offered by Lenovo for the exact model, or use Update driver.
Administrator permission is required to roll back or uninstall a driver. Do not uninstall the device unless updating or rolling back fails.
About the 25H2 claim
Microsoft’s Windows 11 25H2 release-health page does not list this particular tiny red upper-left outline as a known issue.^5^ Reports generated by AI or found in forums do not establish it as a confirmed 25H2 regression.
Windows preview documentation does describe a capture indicator changing from yellow to red, but that documentation applies to a specific experimental Insider build, not enough to attribute the behavior on a standard 25H2 installation.^6^
If clean boot and driver testing do not identify it, report it through Feedback Hub:
- Press Windows+F.
- Select Report a problem.
- Choose Recreate my problem → Start recording.
- Switch applications or tabs until the flash occurs, then stop recording and submit.
Feedback Hub can attach the reproduction recording and diagnostics needed to investigate intermittent UI behavior.^7^
References
- Screen capture
- Windows background apps and your privacy
- How to perform a clean boot in Windows | Microsoft Support
- [Windows 11](https://support.microsoft.com/windows/hardware/display-graphics/troubleshoot-screen-flickering-in-windows)
- Windows 11, version 25H2 known issues and notifications
- Windows 11 Insider Experimental Preview Build 26340.9482
- Send feedback to Microsoft with the Feedback Hub app | Microsoft Support