Something has happened to Windows 11 Professional within the last two weeks that has made the taskbar window switching no longer work reliably. It sometimes works just like it should, and seemingly at random it does not work.
As you know, the taskbar categorizes windows so that for example open folders are all under a single Explorer icon, browser windows are all under a browser icon, etc. When you mouse over an icon, it displays a preview of all the windows, and then you can click one of the previews to bring that window to the front. This function has stopped working reliably within the last two weeks, i.e. some time in March 2025. Clicking on the preview simply does nothing. But the most mysterious part is that it only sometimes does this. Not every time. There are no error messages or Windows error sounds. I have failed to pinpoint all of the different instances of reproducibility, but it seems that the easiest way to reproduce this bug is to:
Have a folder open with Windows Explorer in the background.
Right-click Windows Explorer and open any pinned folder, for example Pictures. Click away so it goes into the background
As a result of clicking away from the window, the icon in the taskbar receives a red coloring, like it's busy or there's a dialog window
In this point, you can mouse over the icon and see the previews of your two Explorer windows, but clicking on those previews will not bring forward either of the windows
That is the most reliable method of reproducing the bug, but it also happens in many other instances that I can't effectively pin down the cause of. Also, rarely even those reproduction steps do not actually replicate the bug.
Most often the problem causes irritation when handling single windows. When there is e.g. only one folder open in the background and I try to hover over its preview to switch to it, nothing happens. I can only bring the folder forward by clicking the actual Explorer icon, not the preview. That's how I discovered those reproduction steps, because when the problem occurs with two windows, clicking on the icon can't solve the problem because it won't bring up any window when there's multiple.
I have made no changes to the configuration or operation of Windows this month and the bug only started occurring this month, therefore I suspect that a Windows update has introduced this bug and it needs to be investigated.