1. Press the Win + R keys to open the Run dialog, type regedit into Run, and click/tap on OK to open Registry Editor.

  2. In the left pane of the Registry Editor, browse to the location below. (see screenshot below)

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced

  3. To Change Delay Time to Wait before Showing Taskbar Thumbnails or List
    1. In the right pane of the Advanced key, double click/tap on the ExtendedUIHoverTime DWORD to modify it.
      If you don't have a ExtendedUIHoverTime DWORD, then right click or press and hold on an empty area in the right pane of the Advanced key, click/tap on New and DWORD (32-bit) Value, type ExtendedUIHoverTime, and press Enter.
    2. Select (dot) Decimal, type in how many milliseconds (1000 milliseconds = 1 second) you want for the delay time, click/tap on OK, and go to step 6 below. (see screenshot below)
      If you use a very long delay time (ex: 10000 milliseconds) it will effectively disable taskbar thumbnail previews.

      Change Delay Time to Show Taskbar Thumbnails in Windows 10-taskbar_thumbnail_preview_delay_time-2.png

  4. To Restore Default Delay Time to Wait before Showing Taskbar Thumbnails or List
    1. In the right pane of the Advanced key, right click or press and hold on the ExtendedUIHoverTime DWORD, and click/tap on Delete. (see screenshot below step 2)
    2. Click/tap on Yes to confirm, and go to step 6 below. (see screenshot below)
      Change Delay Time to Show Taskbar Thumbnails in Windows 10-taskbar_thumbnail_preview_delay_time-3.png

  5. Close Registry Editor.

  6. Restart explorer process, or sign out and sign in to apply.


Change Delay Time to Show Taskbar Thumbnails in Windows 10 | Tutorials (tenforums.com)