I have custom taskbar toolbars and have done since Windows 98 when they initially debuted* and lately I'm finding that they're disappearing regularly
AKAIK the registry key that controls the custom toolbars is HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Streams\Desktop, so I'm just wondering if CCleaner includes this in its remit? If it does is there a way to exclude it?
*Pre-emptive nitpicker comment: I know they were actually there since the IE4 Active Desktop but that wasn't an OS release
