Hello Samuel. I think the problem you're seeing Windows flicker between your Lively Wallpaper and a solid black background is due to a conflict between Windows' default desktop wallpaper system and the Lively Wallpaper engine. When Lively deals with dynamic backgrounds, Windows might still be actively in the process of applying its own desktop image below, particularly when you login, wake up from sleep, or initialize the session.
To do this, first prevent Lively Wallpaper from dynamically rendering its background. Open the Lively Wallpaper application, find the active wallpaper and click the three dots next to it, select "Stop." This will turn off dynamic rendering and pass control of the desktop back over to Windows.
Second, change your Windows background to a solid black color. Right-click on the desktop anywhere, then choose "Personalize." In the Background section, choose "Solid color." From the list of colors, choose black. This prevents Windows from attempting to load an image or slideshow behind Lively's interface.
Even if you do that, Windows will still fall back to a wallpaper unless the OS was told not to. To tell it not to, open your Control Panel by pressing Win + R, type control, and hit Enter. Navigate to 'Ease of Access Center', and click on 'Make the computer easier to see'. Scroll down the screen and enable the option 'Remove background images (where available)'. This option prevents windows from drawing any wallpaper whether or not it was already set or had been cached in memory somewhere.
Finally, to get this all finalized and to ensure that Windows is not holding on to the background cache, press Win + R, and use the command:
rundll32.exe user32.dll,UpdatePerUserSystemParameters
This forces Windows to re-read and refresh the display parameters, while removing any background load behavior from cache.
Here's the reference: Turn off Live Wallpaper
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