When you hover over a program on the taskbar, Windows normally shows a small live picture of each open window, so you can pick the right one. Now you only get a plain text list of window titles, or nothing appears at all. When Windows 10 taskbar thumbnail preview not showing slows down switching between documents, a performance or visual effects setting has usually changed.
Taskbar thumbnails rely on the Desktop Window Manager and a visual effect called “Enable Peek” and “Save taskbar thumbnail previews.” If Windows decides to adjust for best performance, or someone turns off animations to speed up an older PC, these previews are among the first things to go.
A policy, a registry tweak, or graphics driver problems can disable them too.
Turning the effects back on usually restores previews immediately.
The feature can also disappear after you install a “performance slot gacor booster” or follow a guide that switches off animations to make an older PC feel faster.
Why This Happens
Previews disappear for these reasons:
- Visual effects were set to “Adjust for best performance.”
- “Enable Peek” or thumbnail previews were turned off.
- A registry value delays previews or limits them to text lists.
- The graphics driver is the basic Microsoft driver, limiting visual effects.
When many windows of the same app are open, Windows may switch to a text list on purpose because the thumbnails would be too small.
Start With These Basic Checks
Turn the visual effects back on.
- Press Windows + R, type sysdm.cpl, and press Enter.
- Open the Advanced tab and select Settings under Performance.
- Choose “Let Windows choose what’s best for my computer,” or tick “Enable Peek” and “Save taskbar thumbnail previews.”
- Also tick “Animations in the taskbar.”
- Select Apply and OK, then hover over a taskbar button.
Hover for a moment longer than usual when testing, because Windows waits a short time before showing the preview. Moving the mouse quickly across buttons never triggers it.
Going a Step Further
Check registry values and drivers.
- Press Windows + R, type regedit, and go to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced.
- If a value named ExtendedUIHoverTime exists with a large number, change it to 400 or delete it.
- Check for a value called NumThumbnails and delete it if you did not create it.
- Restart Windows Explorer from Task Manager.
- Install the correct graphics driver if Device Manager shows Microsoft Basic Display Adapter.
A Word of Caution
Back up registry keys before editing them. On very slow PCs, previews do use some resources, so keep them off if performance matters more than convenience.
Final Thoughts
Missing taskbar previews usually come from performance settings that disabled visual effects. Re-enable Peek and thumbnail previews, check registry tweaks, and install the proper graphics driver.