I've been getting odd registry entries under HKCU that are clearly erroneous, looking like Chinese characters. If I delete them, they will periodically reappear (every few days). In case the picture is not visible, here is an example:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\潣癡獡灩汃敩瑮慐慲敭整獲伮剓来潩慮卬瑥楴杮svas]
"cl"=dword:00000003
[HKEY_CURRENT_USER\潣癡獡灩汃敩瑮慐慲敭整獲伮剓来潩慮卬瑥楴杮svas\cache2]
[HKEY_CURRENT_USER\潣癡獡灩汃敩瑮慐慲敭整獲伮剓来潩慮卬瑥楴杮svas\ext]
I believe the problem is related to Avast Browser Cleanup because I see HKCU\Software\Avast Software\Avast Browser Cleanup, which has the same "cl" data and "cache2" and "ext" subkeys.
I went into the Component settings in Avast Free Anti-virus and the customization for the Browser Cleanup showed the feature unchecked. Regardless, I have now uninstalled the component so we'll see if it reappears.