A mysterious white window is showing up on Windows PCs. Here’s a fix

An increasing number of Windows 10 and Windows 11 users are seeing “white windows” in the corners of their screens, according ...

Blank white window opens every time I log into Windows 11

If you see a blank white window open every time you start or sign in to Windows 11/10, disable Chrome's scheduled Task named ...
Windows Report

Windows 11 and Windows 10 Users Hit by Blank White Window Issue

Windows users report a blank white window after startup or unlock, with a Chrome Task Scheduler entry suspected as a possible ...
Ars Technica

Windows 11 Dark Mode: opening folder window flashes white

I've seen this mentioned on the net, so it happens to others too, and seemingly since Windows 10, but I haven't found much detailed discussions or any fixes. Perhaps it's not that common then. So, I ...