Several hours after each boot the Windows 7 taskbar thumbnail popups stops appear.
Click the currently opened window (it should not be a group of windows) – it will collapse. Than hover the mouse over any other window icon, wait a second, and nothing happens. After that no thumbnail popup windows appear at all.
There is the way to return them back. You need to open two windows of the same application (group of windows), and click their group – two popup thumbnail windows should appear. After that thumbnails are back, until you click currently opened window…
It there a way to fix it?
EDIT: As an experiment I followed the MS Answers forum idea to use Hibernation instead of Stand By mode. And it works! Thumbnail windows are back and stable as they never disappear. The problem is solved. Thanks.
Best Answer
Check this one:
Windows 7 taskbar thumbnail preview, aero preview not working
and have you troubleshooted?