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SuperNova Displays Black Screen on Windows Lock Screen After Installing KB5120998

Lock screen becomes inaccessible when SuperNova is running on Windows 11 25H2 systems with KB5120998 installed

 Overview

Some users may experience an issue when locking their computer while Dolphin SuperNova is running. Instead of the standard Windows lock screen appearing, the screen remains black with the SuperNova focus highlight visible. In this state, the lock screen cannot be interacted with and the user may be unable to sign back in normally.

Affected Configurations

  • Operating System: Windows 11 25H2 
  • SuperNova Version: Reproduced with SuperNova 25.05 Build 3954
  • Windows Update: KB5120998 installed

Symptoms

After locking the computer:

  • The display shows a black screen.
  • The SuperNova focus highlight remains visible.
  • The Windows lock screen does not render correctly.
  • Keyboard interaction with the lock screen is unavailable.

Cause

Investigation has identified Windows Update KB5120998 as the trigger for this behaviour. The issue occurs when SuperNova is running and the system is locked after the update has been installed.

Status

Dolphin has identified and reproduced this issue and confirmed that it is triggered by the installation of KB5120998 on affected Windows 11 25H2 systems. Our Development Team is actively investigating the problem and working on a software update to restore normal lock screen functionality when SuperNova is running.

Workaround

Until a permanent fix is available, affected users may be able to restore normal behaviour by uninstalling Windows Update KB5120998:

  1. Open Settings > Windows Update > Update History.
  2. Select Uninstall updates.
  3. Locate KB5120998.
  4. Choose Uninstall and restart the computer when prompted.

Alternatively, users can temporarily avoid locking the computer while SuperNova is running.

Note: Uninstalling a Windows update may remove security or reliability fixes delivered by Microsoft. Users should review their organisation's update policies before removing KB5120998.

Dolphin will provide further updates once a permanent resolution is available.

This article was last updated 29/09/2026.