I ran into an interesting problem the other day when someone’s Windows 7 taskbar would not autohide in spite of being set to do so. This was definitely a problem I had to google for a solution, since I had never ran across this type of issue before.
It seems that misbehaving programs can prevent the Windows 7 taskbar from hiding if they are sending notifications to the taskbar. However, I suspected that was not the problem here, as it had worked until someone started playing with it.
Turns out that you can clear out the registry settings for it and reset the Windows 7 taskbar settings that way. According to the Microsoft Community article “Taskbar does not Auto-hide all the time Windows 7“:
In Regedit, navigate to:
delete the value named ‘Toolbars’.
In Task Manager, select ‘File’ -> ‘New Task’ -> type ‘explorer’ to restart the shell.
If that doesn’t do the trick, repeat deleting ‘TaskbarWinXP’ as well. (I can’t test right now).