Mark,
You can try this below. It will reset the default value in the registry for this.
1. Open regedit.
2. Go to:
HKEY_CLASSES_ROOT\Directory\shell
3. In the right pane, right click on
(Default) and click
Modify.
4. Type
none and click
OK.
Here's a REG download if you prefer to use it instead. After you download it onto the desktop, right click on it and click
Merge. Approve all the security prompts. This will change the registry for you automatically.
HKCR_Directory_Shell_None.reg < Click to Download
Hope this helps,
Shawn